diff --git a/src/battle_main.c b/src/battle_main.c
index 0083b2f06..681230482 100644
--- a/src/battle_main.c
+++ b/src/battle_main.c
@@ -792,8 +792,7 @@ static void SetPlayerBerryDataInBattleStruct(void)
 
 static void SetAllPlayersBerryData(void)
 {
-    s32 i;
-    s32 j;
+    s32 i, j;
 
     if (!(gBattleTypeFlags & BATTLE_TYPE_LINK))
     {
diff --git a/src/battle_util.c b/src/battle_util.c
index ece2eade9..bad9457a2 100644
--- a/src/battle_util.c
+++ b/src/battle_util.c
@@ -405,8 +405,7 @@ u8 CheckMoveLimitations(u8 battlerId, u8 unusableMoves, u8 check)
 #define ALL_MOVES_MASK ((1 << MAX_MON_MOVES) - 1)
 bool8 AreAllMovesUnusable(void)
 {
-    u8 unusable;
-    unusable = CheckMoveLimitations(gActiveBattler, 0, MOVE_LIMITATIONS_ALL);
+    u8 unusable = CheckMoveLimitations(gActiveBattler, 0, MOVE_LIMITATIONS_ALL);
 
     if (unusable == ALL_MOVES_MASK) // All moves are unusable.
     {
@@ -523,7 +522,7 @@ u8 DoFieldEndTurnEffects(void)
                 if (effect != 0)
                     break;
             }
-            if (!effect)
+            if (effect == 0)
             {
                 gBattleStruct->turnCountersTracker++;
                 gBattleStruct->turnSideTracker = 0;
@@ -549,7 +548,7 @@ u8 DoFieldEndTurnEffects(void)
                 if (effect != 0)
                     break;
             }
-            if (!effect)
+            if (effect == 0)
             {
                 gBattleStruct->turnCountersTracker++;
                 gBattleStruct->turnSideTracker = 0;
@@ -560,8 +559,7 @@ u8 DoFieldEndTurnEffects(void)
             {
                 side = gBattleStruct->turnSideTracker;
                 gActiveBattler = gBattlerAttacker = gSideTimers[side].mistBattlerId;
-                if (gSideTimers[side].mistTimer != 0
-                 && --gSideTimers[side].mistTimer == 0)
+                if (gSideTimers[side].mistTimer != 0 && --gSideTimers[side].mistTimer == 0)
                 {
                     gSideStatuses[side] &= ~SIDE_STATUS_MIST;
                     BattleScriptExecute(BattleScript_SideStatusWoreOff);
@@ -573,7 +571,7 @@ u8 DoFieldEndTurnEffects(void)
                 if (effect != 0)
                     break;
             }
-            if (!effect)
+            if (effect == 0)
             {
                 gBattleStruct->turnCountersTracker++;
                 gBattleStruct->turnSideTracker = 0;
@@ -597,7 +595,7 @@ u8 DoFieldEndTurnEffects(void)
                 if (effect != 0)
                     break;
             }
-            if (!effect)
+            if (effect == 0)
             {
                 gBattleStruct->turnCountersTracker++;
                 gBattleStruct->turnSideTracker = 0;
@@ -619,7 +617,7 @@ u8 DoFieldEndTurnEffects(void)
                 if (effect != 0)
                     break;
             }
-            if (!effect)
+            if (effect == 0)
             {
                 gBattleStruct->turnCountersTracker++;
             }
@@ -1544,8 +1542,8 @@ u8 AtkCanceller_UnableToUseMove(void)
 
 bool8 HasNoMonsToSwitch(u8 battler, u8 partyIdBattlerOn1, u8 partyIdBattlerOn2)
 {
+    u8 playerId, flankId;
     struct Pokemon *party;
-    u8 id1, id2;
     s32 i;
 
     if (!(gBattleTypeFlags & BATTLE_TYPE_DOUBLE))
@@ -1553,41 +1551,41 @@ bool8 HasNoMonsToSwitch(u8 battler, u8 partyIdBattlerOn1, u8 partyIdBattlerOn2)
 
     if (gBattleTypeFlags & BATTLE_TYPE_MULTI)
     {
-        id2 = GetBattlerMultiplayerId(battler);
+        flankId = GetBattlerMultiplayerId(battler);
         if (GetBattlerSide(battler) == B_SIDE_PLAYER)
             party = gPlayerParty;
         else
             party = gEnemyParty;
 
-        id1 = GetLinkTrainerFlankId(id2);
-        for (i = id1 * MULTI_PARTY_SIZE; i < id1 * MULTI_PARTY_SIZE + MULTI_PARTY_SIZE; i++)
+        playerId = GetLinkTrainerFlankId(flankId);
+        for (i = playerId * MULTI_PARTY_SIZE; i < playerId * MULTI_PARTY_SIZE + MULTI_PARTY_SIZE; i++)
         {
             if (GetMonData(&party[i], MON_DATA_HP) != 0
              && GetMonData(&party[i], MON_DATA_SPECIES2) != SPECIES_NONE
              && GetMonData(&party[i], MON_DATA_SPECIES2) != SPECIES_EGG)
                 break;
         }
-        return (i == id1 * MULTI_PARTY_SIZE + MULTI_PARTY_SIZE);
+        return (i == playerId * MULTI_PARTY_SIZE + MULTI_PARTY_SIZE);
     }
     else
     {
         if (GetBattlerSide(battler) == B_SIDE_OPPONENT)
         {
-            id2 = GetBattlerAtPosition(B_POSITION_OPPONENT_LEFT);
-            id1 = GetBattlerAtPosition(B_POSITION_OPPONENT_RIGHT);
+            flankId = GetBattlerAtPosition(B_POSITION_OPPONENT_LEFT);
+            playerId = GetBattlerAtPosition(B_POSITION_OPPONENT_RIGHT);
             party = gEnemyParty;
         }
         else
         {
-            id2 = GetBattlerAtPosition(B_POSITION_PLAYER_LEFT);
-            id1 = GetBattlerAtPosition(B_POSITION_PLAYER_RIGHT);
+            flankId = GetBattlerAtPosition(B_POSITION_PLAYER_LEFT);
+            playerId = GetBattlerAtPosition(B_POSITION_PLAYER_RIGHT);
             party = gPlayerParty;
         }
 
         if (partyIdBattlerOn1 == PARTY_SIZE)
-            partyIdBattlerOn1 = gBattlerPartyIndexes[id2];
+            partyIdBattlerOn1 = gBattlerPartyIndexes[flankId];
         if (partyIdBattlerOn2 == PARTY_SIZE)
-            partyIdBattlerOn2 = gBattlerPartyIndexes[id1];
+            partyIdBattlerOn2 = gBattlerPartyIndexes[playerId];
 
         for (i = 0; i < PARTY_SIZE; i++)
         {
@@ -1595,7 +1593,7 @@ bool8 HasNoMonsToSwitch(u8 battler, u8 partyIdBattlerOn1, u8 partyIdBattlerOn2)
              && GetMonData(&party[i], MON_DATA_SPECIES2) != SPECIES_NONE
              && GetMonData(&party[i], MON_DATA_SPECIES2) != SPECIES_EGG
              && i != partyIdBattlerOn1 && i != partyIdBattlerOn2
-             && i != *(gBattleStruct->monToSwitchIntoId + id2) && i != id1[gBattleStruct->monToSwitchIntoId])
+             && i != *(gBattleStruct->monToSwitchIntoId + flankId) && i != playerId[gBattleStruct->monToSwitchIntoId])
                 break;
         }
         return (i == PARTY_SIZE);
@@ -2375,7 +2373,7 @@ u8 AbilityBattleEffects(u8 caseID, u8 battler, u8 ability, u8 special, u16 moveA
                     break;
                 }
             }
-            if (!effect)
+            if (effect == 0)
             {
                 for (i = 0; i < gBattlersCount; i++)
                 {