diff --git a/src/activity_item_handling.cpp b/src/activity_item_handling.cpp
index ced8479c030ca..b52b8aa7e7fa7 100644
--- a/src/activity_item_handling.cpp
+++ b/src/activity_item_handling.cpp
@@ -849,7 +849,7 @@ static activity_reason_info find_base_construction(
     const inventory &inv,
     const tripoint &loc,
     const cata::optional<construction_id> &part_con_idx,
-    const construction_id idx,
+    const construction_id &idx,
     std::set<construction_id> &used )
 {
     const construction &build = idx.obj();
diff --git a/src/avatar_action.cpp b/src/avatar_action.cpp
index 4e76f3a0e943e..c089d2b4d0af8 100644
--- a/src/avatar_action.cpp
+++ b/src/avatar_action.cpp
@@ -853,7 +853,7 @@ void avatar_action::fire_ranged_mutation( avatar &you, const item &fake_gun )
 }
 
 void avatar_action::fire_ranged_bionic( avatar &you, const item &fake_gun,
-                                        units::energy cost_per_shot )
+                                        const units::energy &cost_per_shot )
 {
     you.assign_activity( aim_activity_actor::use_bionic( fake_gun, cost_per_shot ), false );
 }
@@ -950,7 +950,7 @@ void avatar_action::eat( avatar &you )
     avatar_action::eat( you, loc, true );
 }
 
-void avatar_action::eat( avatar &you, item_location loc, bool open_consume_menu )
+void avatar_action::eat( avatar &you, const item_location &loc, bool open_consume_menu )
 {
     if( !loc ) {
         you.cancel_activity();
diff --git a/src/avatar_action.h b/src/avatar_action.h
index 1aac0cac95958..8610aef7cabe3 100644
--- a/src/avatar_action.h
+++ b/src/avatar_action.h
@@ -18,7 +18,7 @@ namespace avatar_action
 
 /** Eat food or fuel  'E' (or 'a') */
 void eat( avatar &you );
-void eat( avatar &you, item_location loc, bool open_consume_menu = false );
+void eat( avatar &you, const item_location &loc, bool open_consume_menu = false );
 // special rules for eating: grazing etc
 // returns false if no rules are needed
 bool eat_here( avatar &you );
@@ -55,7 +55,7 @@ void fire_wielded_weapon( avatar &you );
 void fire_ranged_mutation( avatar &you, const item &fake_gun );
 
 /** Stores fake gun specified by the bionic and starts interactive aiming */
-void fire_ranged_bionic( avatar &you, const item &fake_gun, units::energy cost_per_shot );
+void fire_ranged_bionic( avatar &you, const item &fake_gun, const units::energy &cost_per_shot );
 
 /**
  * Checks if the player can manually (with their 2 hands, not via vehicle controls)
diff --git a/src/bionics.cpp b/src/bionics.cpp
index 659024d53d275..999f95efc93af 100644
--- a/src/bionics.cpp
+++ b/src/bionics.cpp
@@ -256,7 +256,7 @@ bool bionic_data::is_included( const bionic_id &id ) const
     return std::find( included_bionics.begin(), included_bionics.end(), id ) != included_bionics.end();
 }
 
-void bionic_data::load( const JsonObject &jsobj, const std::string )
+void bionic_data::load( const JsonObject &jsobj, const std::string & )
 {
 
     mandatory( jsobj, was_loaded, "id", id );
@@ -1942,7 +1942,7 @@ void Character::consume_anesth_requirment( const itype &cbm, player &patient )
     invalidate_crafting_inventory();
 }
 
-bool Character::has_installation_requirment( bionic_id bid )
+bool Character::has_installation_requirment( const bionic_id &bid )
 {
     if( bid->installation_requirement.is_empty() ) {
         return false;
@@ -1960,7 +1960,7 @@ bool Character::has_installation_requirment( bionic_id bid )
     return true;
 }
 
-void Character::consume_installation_requirment( bionic_id bid )
+void Character::consume_installation_requirment( const bionic_id &bid )
 {
     for( const auto &e : bid->installation_requirement->get_components() ) {
         as_player()->consume_items( e, 1, is_crafting_component );
diff --git a/src/bionics.h b/src/bionics.h
index 848025985341f..a2fcb452ab353 100644
--- a/src/bionics.h
+++ b/src/bionics.h
@@ -133,7 +133,7 @@ struct bionic_data {
     bool is_included( const bionic_id &id ) const;
 
     bool was_loaded = false;
-    void load( const JsonObject &obj, std::string );
+    void load( const JsonObject &obj, const std::string & );
     static void load_bionic( const JsonObject &jo, const std::string &src );
     static const std::vector<bionic_data> &get_all();
     static void check_bionic_consistency();
diff --git a/src/character.cpp b/src/character.cpp
index 4971bbb140120..51a4e79ac63b9 100644
--- a/src/character.cpp
+++ b/src/character.cpp
@@ -1579,7 +1579,7 @@ void Character::add_effect( const efftype_id &eff_id, const time_duration &dur,
     Creature::add_effect( eff_id, dur, bp, permanent, intensity, force, deferred );
 }
 
-void Character::expose_to_disease( const diseasetype_id dis_type )
+void Character::expose_to_disease( const diseasetype_id &dis_type )
 {
     const cata::optional<int> &healt_thresh = dis_type->health_threshold;
     if( healt_thresh && healt_thresh.value() < get_healthy() ) {
diff --git a/src/character.h b/src/character.h
index 11fea7f003926..a3addead9a5e7 100644
--- a/src/character.h
+++ b/src/character.h
@@ -580,7 +580,7 @@ class Character : public Creature, public visitable<Character>
                          int intensity = 0, bool force = false, bool deferred = false ) override;
 
         /**Determine if character is susceptible to dis_type and if so apply the symptoms*/
-        void expose_to_disease( diseasetype_id dis_type );
+        void expose_to_disease( const diseasetype_id &dis_type );
         /**
          * Handles end-of-turn processing.
          */
@@ -1054,8 +1054,8 @@ class Character : public Creature, public visitable<Character>
         bool has_enough_anesth( const itype &cbm );
         void consume_anesth_requirment( const itype &cbm, player &patient );
         /**Has the required equipement for manual installation*/
-        bool has_installation_requirment( bionic_id bid );
-        void consume_installation_requirment( bionic_id bid );
+        bool has_installation_requirment( const bionic_id &bid );
+        void consume_installation_requirment( const bionic_id &bid );
         /** Handles process of introducing patient into anesthesia during Autodoc operations. Requires anesthesia kits or NOPAIN mutation */
         void introduce_into_anesthesia( const time_duration &duration, player &installer,
                                         bool needs_anesthesia );
diff --git a/src/creature.cpp b/src/creature.cpp
index c3ca572559fc1..1e83ad7ea51c2 100644
--- a/src/creature.cpp
+++ b/src/creature.cpp
@@ -1424,7 +1424,7 @@ anatomy_id Creature::get_anatomy() const
     return creature_anatomy;
 }
 
-void Creature::set_anatomy( anatomy_id anat )
+void Creature::set_anatomy( const anatomy_id &anat )
 {
     creature_anatomy = anat;
 }
diff --git a/src/creature.h b/src/creature.h
index 0d3393ba882ff..3750446236ac9 100644
--- a/src/creature.h
+++ b/src/creature.h
@@ -453,7 +453,7 @@ class Creature
 
         anatomy_id creature_anatomy = anatomy_id( "default_anatomy" );
         anatomy_id get_anatomy() const;
-        void set_anatomy( anatomy_id anat );
+        void set_anatomy( const anatomy_id &anat );
 
         bodypart_id get_random_body_part( bool main = false ) const;
         /**
diff --git a/src/faction_camp.cpp b/src/faction_camp.cpp
index 37e8393d9244d..45729ae440b52 100644
--- a/src/faction_camp.cpp
+++ b/src/faction_camp.cpp
@@ -436,8 +436,8 @@ time_duration companion_travel_time_calc( const std::vector<tripoint> &journey,
 int om_carry_weight_to_trips( const std::vector<item *> &itms, npc_ptr comp = nullptr );
 /// Determines how many trips it takes to move @ref mass and @ref volume of items
 /// with @ref carry_mass and @ref carry_volume moved per trip
-int om_carry_weight_to_trips( units::mass mass, units::volume volume, units::mass carry_mass,
-                              units::volume carry_volume );
+int om_carry_weight_to_trips( const units::mass &mass, const units::volume &volume,
+                              const units::mass &carry_mass, const units::volume &carry_volume );
 /// Formats the variables into a standard looking description to be displayed in a ynquery window
 std::string camp_trip_description( const time_duration &total_time,
                                    const time_duration &working_time,
@@ -3492,8 +3492,8 @@ time_duration companion_travel_time_calc( const std::vector<tripoint> &journey,
     return work + one_way * trips * 1_seconds;
 }
 
-int om_carry_weight_to_trips( units::mass mass, units::volume volume,
-                              units::mass carry_mass, units::volume carry_volume )
+int om_carry_weight_to_trips( const units::mass &mass, const units::volume &volume,
+                              const units::mass &carry_mass, const units::volume &carry_volume )
 {
     int trips_m = 1 + mass / carry_mass;
     int trips_v = 1 + volume / carry_volume;
diff --git a/src/game.cpp b/src/game.cpp
index 88626599bcd07..81d5ee923d8c9 100644
--- a/src/game.cpp
+++ b/src/game.cpp
@@ -2053,7 +2053,7 @@ void game::handle_key_blocking_activity()
 
 // call on_contents_changed() for the location's parent and all the way up the chain
 // used in game::inventory_item_menu()
-static void handle_contents_changed( item_location acted_item )
+static void handle_contents_changed( const item_location &acted_item )
 {
     if( acted_item.where() != item_location::type::container ) {
         return;
diff --git a/src/game_inventory.cpp b/src/game_inventory.cpp
index 2dadaa408bceb..aa3ae985d4214 100644
--- a/src/game_inventory.cpp
+++ b/src/game_inventory.cpp
@@ -242,7 +242,7 @@ void game_menus::inv::common( avatar &you )
     } while( loop_options.count( res ) != 0 );
 }
 
-void game_menus::inv::common( item_location loc, avatar &you )
+void game_menus::inv::common( item_location &loc, avatar &you )
 {
     // Return to inventory menu on those inputs
     static const std::set<int> loop_options = { { '\0', '=', 'f' } };
@@ -1274,7 +1274,7 @@ class holster_inventory_preset: public weapon_inventory_preset
         const item &holster;
 };
 
-drop_locations game_menus::inv::holster( player &p, item_location holster )
+drop_locations game_menus::inv::holster( player &p, const item_location &holster )
 {
     const std::string holster_name = holster->tname( 1, false );
     const use_function *use = holster->type->get_use( "holster" );
@@ -1300,7 +1300,7 @@ drop_locations game_menus::inv::holster( player &p, item_location holster )
     return insert_menu.execute();
 }
 
-void game_menus::inv::insert_items( avatar &you, item_location holster )
+void game_menus::inv::insert_items( avatar &you, item_location &holster )
 {
     drop_locations holstered_list = game_menus::inv::holster( you, holster );
     for( drop_location holstered_item : holstered_list ) {
diff --git a/src/game_inventory.h b/src/game_inventory.h
index 92a21238a458e..b4b75d40a33ab 100644
--- a/src/game_inventory.h
+++ b/src/game_inventory.h
@@ -64,7 +64,7 @@ item_location titled_filter_menu( item_location_filter filter, avatar &you,
 /*@{*/
 
 void common( avatar &you );
-void common( item_location loc, avatar &you );
+void common( item_location &loc, avatar &you );
 void compare( player &p, const cata::optional<tripoint> &offset );
 void reassign_letter( player &p, item &it );
 void swap_letters( player &p );
@@ -98,8 +98,8 @@ item_location use( avatar &you );
 /** Item wielding/unwielding menu. */
 item_location wield( avatar &you );
 /** Item wielding/unwielding menu. */
-drop_locations holster( player &p, item_location holster );
-void insert_items( avatar &you, item_location holster );
+drop_locations holster( player &p, const item_location &holster );
+void insert_items( avatar &you, item_location &holster );
 /** Choosing a gun to saw down it's barrel. */
 item_location saw_barrel( player &p, item &tool );
 /** Choose item to wear. */
diff --git a/src/handle_liquid.cpp b/src/handle_liquid.cpp
index 7cceff2a2f634..1e6098638f134 100644
--- a/src/handle_liquid.cpp
+++ b/src/handle_liquid.cpp
@@ -76,7 +76,7 @@ static void serialize_liquid_target( player_activity &act, const vehicle &veh )
     act.coords.push_back( veh.global_pos3() );
 }
 
-static void serialize_liquid_target( player_activity &act, item_location container_item )
+static void serialize_liquid_target( player_activity &act, const item_location &container_item )
 {
     act.values.push_back( LTT_CONTAINER );
     act.values.push_back( 0 ); // dummy
diff --git a/src/inventory_ui.cpp b/src/inventory_ui.cpp
index 775d06fc200a3..6bf161c977655 100644
--- a/src/inventory_ui.cpp
+++ b/src/inventory_ui.cpp
@@ -920,7 +920,7 @@ int inventory_column::reassign_custom_invlets( const player &p, int min_invlet,
     return cur_invlet;
 }
 
-static int num_parents( item_location loc )
+static int num_parents( const item_location &loc )
 {
     if( loc.where() != item_location::type::container ) {
         return 0;
@@ -1267,12 +1267,12 @@ void inventory_selector::add_items( inventory_column &target_column,
     }
 }
 
-void inventory_selector::add_contained_items( item_location container )
+void inventory_selector::add_contained_items( item_location &container )
 {
     add_contained_items( container, own_inv_column );
 }
 
-void inventory_selector::add_contained_items( item_location container, inventory_column &column )
+void inventory_selector::add_contained_items( item_location &container, inventory_column &column )
 {
     for( item *it : container->contents.all_items_top() ) {
         item_location child( container, it );
diff --git a/src/inventory_ui.h b/src/inventory_ui.h
index c3acfa15b5d5e..85bacdb29c6ae 100644
--- a/src/inventory_ui.h
+++ b/src/inventory_ui.h
@@ -474,8 +474,8 @@ class inventory_selector
         inventory_selector( player &u, const inventory_selector_preset &preset = default_preset );
         virtual ~inventory_selector();
         /** These functions add items from map / vehicles. */
-        void add_contained_items( item_location container );
-        void add_contained_items( item_location container, inventory_column &column );
+        void add_contained_items( item_location &container );
+        void add_contained_items( item_location &container, inventory_column &column );
         void add_character_items( Character &character );
         void add_map_items( const tripoint &target );
         void add_vehicle_items( const tripoint &target );
diff --git a/src/iuse_actor.cpp b/src/iuse_actor.cpp
index 03c6cc3e82fcd..af3788de587fd 100644
--- a/src/iuse_actor.cpp
+++ b/src/iuse_actor.cpp
@@ -2482,7 +2482,8 @@ int holster_actor::use( player &p, item &it, bool, const tripoint & ) const
             return 0;
         }
         // may not strictly be the correct item_location, but plumbing item_location through all iuse_actor::use won't work
-        game_menus::inv::insert_items( *p.as_avatar(), item_location( p, &it ) );
+        item_location item_loc( p, &it );
+        game_menus::inv::insert_items( *p.as_avatar(), item_loc );
     }
 
     return 0;
diff --git a/src/mapgen.cpp b/src/mapgen.cpp
index e8dab2906e290..0225d333378d9 100644
--- a/src/mapgen.cpp
+++ b/src/mapgen.cpp
@@ -226,7 +226,7 @@ class mapgen_basic_container
         weighted_int_list<std::shared_ptr<mapgen_function>> weights_;
 
     public:
-        int add( const std::shared_ptr<mapgen_function> ptr ) {
+        int add( const std::shared_ptr<mapgen_function> &ptr ) {
             assert( ptr );
             mapgens_.push_back( ptr );
             return mapgens_.size() - 1;
@@ -334,7 +334,7 @@ class mapgen_factory
             return mapgens_.count( key ) != 0;
         }
         /// @see mapgen_basic_container::add
-        int add( const std::string &key, const std::shared_ptr<mapgen_function> ptr ) {
+        int add( const std::string &key, const std::shared_ptr<mapgen_function> &ptr ) {
             return mapgens_[key].add( ptr );
         }
         /// @see mapgen_basic_container::generate
diff --git a/src/npc.h b/src/npc.h
index 64b63271cdf41..5f57dfca329ac 100644
--- a/src/npc.h
+++ b/src/npc.h
@@ -1162,7 +1162,8 @@ class npc : public player
         // Move to, or grab, our targeted item
         void pick_up_item();
         // Drop wgt and vol, including all items with less value than min_val
-        void drop_items( units::mass drop_weight, units::volume drop_volume, int min_val = 0 );
+        void drop_items( const units::mass &drop_weight, const units::volume &drop_volume,
+                         int min_val = 0 );
         /** Picks up items and returns a list of them. */
         std::list<item> pick_up_item_map( const tripoint &where );
         std::list<item> pick_up_item_vehicle( vehicle &veh, int part_index );
diff --git a/src/npcmove.cpp b/src/npcmove.cpp
index 0fa5adbc83a6b..8e3ce03118e50 100644
--- a/src/npcmove.cpp
+++ b/src/npcmove.cpp
@@ -3081,7 +3081,8 @@ struct ratio_index {
 };
 
 /* As of October 2019, this is buggy, do not use!! */
-void npc::drop_items( units::mass drop_weight, units::volume drop_volume, int min_val )
+void npc::drop_items( const units::mass &drop_weight, const units::volume &drop_volume,
+                      int min_val )
 {
     /* Remove this when someone debugs it back to functionality */
     return;
diff --git a/src/output.cpp b/src/output.cpp
index 0fe13bc48c4a2..efe4b75915291 100644
--- a/src/output.cpp
+++ b/src/output.cpp
@@ -520,7 +520,7 @@ void draw_custom_border(
     const catacurses::window &w, const catacurses::chtype ls, const catacurses::chtype rs,
     const catacurses::chtype ts, const catacurses::chtype bs, const catacurses::chtype tl,
     const catacurses::chtype tr, const catacurses::chtype bl, const catacurses::chtype br,
-    const nc_color FG, const point &pos, int height, int width )
+    const nc_color &FG, const point &pos, int height, int width )
 {
     wattron( w, FG );
 
diff --git a/src/output.h b/src/output.h
index e99885c5737dc..6fbdf1db0a4bb 100644
--- a/src/output.h
+++ b/src/output.h
@@ -367,7 +367,7 @@ void draw_custom_border(
     const catacurses::window &w, catacurses::chtype ls = 1, catacurses::chtype rs = 1,
     catacurses::chtype ts = 1, catacurses::chtype bs = 1, catacurses::chtype tl = 1,
     catacurses::chtype tr = 1, catacurses::chtype bl = 1, catacurses::chtype br = 1,
-    nc_color FG = BORDER_COLOR, const point &pos = point_zero, int height = 0, int width = 0 );
+    const nc_color &FG = BORDER_COLOR, const point &pos = point_zero, int height = 0, int width = 0 );
 void draw_border( const catacurses::window &w, nc_color border_color = BORDER_COLOR,
                   const std::string &title = "", nc_color title_color = c_light_red );
 void draw_border_below_tabs( const catacurses::window &w, nc_color border_color = BORDER_COLOR );
diff --git a/src/stomach.cpp b/src/stomach.cpp
index 884a70a767ae0..a3c31c9ecbb64 100644
--- a/src/stomach.cpp
+++ b/src/stomach.cpp
@@ -118,7 +118,7 @@ stomach_contents::stomach_contents( units::volume max_vol, bool is_stomach )
     last_ate = calendar::before_time_starts;
 }
 
-static std::string ml_to_string( units::volume vol )
+static std::string ml_to_string( const units::volume &vol )
 {
     return to_string( units::to_milliliter<int>( vol ) ) + "_ml";
 }
@@ -274,7 +274,7 @@ void stomach_contents::mod_nutr( int nutr )
     mod_calories( -1 * std::round( nutr * 2500.0f / ( 12 * 24 ) ) );
 }
 
-void stomach_contents::mod_water( units::volume h2o )
+void stomach_contents::mod_water( const units::volume &h2o )
 {
     if( h2o > 0_ml ) {
         water += h2o;
@@ -286,7 +286,7 @@ void stomach_contents::mod_quench( int quench )
     mod_water( 5_ml * quench );
 }
 
-void stomach_contents::mod_contents( units::volume vol )
+void stomach_contents::mod_contents( const units::volume &vol )
 {
     if( -vol >= contents ) {
         contents = 0_ml;
diff --git a/src/stomach.h b/src/stomach.h
index 47878018c23a8..3a95c0f835f84 100644
--- a/src/stomach.h
+++ b/src/stomach.h
@@ -132,12 +132,12 @@ class stomach_contents
         void mod_nutr( int nutr );
         // changes water amount in stomach
         // overflow draws from player thirst
-        void mod_water( units::volume h2o );
+        void mod_water( const units::volume &h2o );
         // changes water amount in stomach converted from quench value
         // TODO: Move to mL values of water
         void mod_quench( int quench );
         // adds volume to your stomach
-        void mod_contents( units::volume vol );
+        void mod_contents( const units::volume &vol );
 
         // how long has it been since i ate?
         // only really relevant for player::stomach
diff --git a/src/veh_interact.cpp b/src/veh_interact.cpp
index f9bc934de04a3..fd6610ecc6002 100644
--- a/src/veh_interact.cpp
+++ b/src/veh_interact.cpp
@@ -668,7 +668,7 @@ bool veh_interact::can_self_jack()
     return false;
 }
 
-static void print_message_to( catacurses::window &w_msg, const nc_color col,
+static void print_message_to( catacurses::window &w_msg, const nc_color &col,
                               const std::string &msg )
 {
     werase( w_msg );