diff --git a/src/alchemy.c b/src/alchemy.c
index 5e369a3e1..cf4dc6f73 100644
--- a/src/alchemy.c
+++ b/src/alchemy.c
@@ -123,9 +123,14 @@ static void end_potion(unit * u, const potion_type * ptype, int amount)
 }
 
 static int potion_water_of_life(unit * u, region *r, int amount) {
+    static int config;
+    static int tree_type, tree_count;
     int wood = 0;
-    int tree_type = config_get_int("rules.magic.wol_type", 1);
-    int tree_count = config_get_int("rules.magic.wol_effect", 10);
+
+    if (config_changed(&config)) {
+        tree_type = config_get_int("rules.magic.wol_type", 1);
+        tree_count = config_get_int("rules.magic.wol_effect", 10);
+    }
     /* mallorn is required to make mallorn forests, wood for regular ones */
     if (fval(r, RF_MALLORN)) {
         wood = use_pooled(u, rt_find("mallorn"),
diff --git a/src/battle.c b/src/battle.c
index 3ab117c2a..4686a942a 100644
--- a/src/battle.c
+++ b/src/battle.c
@@ -141,6 +141,7 @@ static int rule_goblin_bonus;
 static int rule_tactics_formula;
 static int rule_nat_armor;
 static int rule_cavalry_mode;
+static int rule_vampire;
 
 static const curse_type *peace_ct, *slave_ct, *calm_ct;
 
@@ -159,6 +160,7 @@ static void init_rules(void)
     rule_anon_battle = config_get_int("rules.stealth.anon_battle", 1) != 0;
     rule_cavalry_mode = config_get_int("rules.cavalry.mode", 1);
     rule_cavalry_skill = config_get_int("rules.cavalry.skill", 2);
+    rule_vampire = config_get_int("rules.combat.demon_vampire", 0);
     rule_loot = config_get_int("rules.combat.loot",
         LOOT_MONSTERS | LOOT_OTHERS | LOOT_KEEPLOOT);
     /* new formula to calculate to-hit-chance */
@@ -1009,11 +1011,10 @@ const char *rel_dam(int dam, int hp)
 
 static void vampirism(troop at, int damage)
 {
-    int vampire = config_get_int("rules.combat.demon_vampire", 0);
-    if (vampire > 0) {
-        int gain = damage / vampire;
-        int chance = damage - vampire * gain;
-        if (chance > 0 && (rng_int() % vampire < chance))
+    if (rule_vampire > 0) {
+        int gain = damage / rule_vampire;
+        int chance = damage - rule_vampire * gain;
+        if (chance > 0 && (rng_int() % rule_vampire < chance))
             ++gain;
         if (gain > 0) {
             int maxhp = unit_max_hp(at.fighter->unit);
diff --git a/src/kernel/build.c b/src/kernel/build.c
index 6bea3e6b4..6bc953241 100644
--- a/src/kernel/build.c
+++ b/src/kernel/build.c
@@ -419,8 +419,9 @@ int value)
 
 int roqf_factor(void)
 {
-    int value = -1;
-    if (value < 0) {
+    static int config;
+    static int value;
+    if (config_changed(&config)) {
         value = config_get_int("rules.economy.roqf", 10);
     }
     return value;
diff --git a/src/kernel/build.test.c b/src/kernel/build.test.c
index c0775051e..9ea473725 100644
--- a/src/kernel/build.test.c
+++ b/src/kernel/build.test.c
@@ -394,10 +394,19 @@ static void test_build_destroy_cmd(CuTest *tc) {
     test_cleanup();
 }
 
+static void test_build_roqf_factor(CuTest *tc) {
+    test_setup();
+    CuAssertIntEquals(tc, 10, roqf_factor());
+    config_set("rules.economy.roqf", "50");
+    CuAssertIntEquals(tc, 50, roqf_factor());
+    test_cleanup();
+}
+
 CuSuite *get_build_suite(void)
 {
     CuSuite *suite = CuSuiteNew();
     SUITE_ADD_TEST(suite, test_build_limits);
+    SUITE_ADD_TEST(suite, test_build_roqf_factor);
     SUITE_ADD_TEST(suite, test_build_failure_low_skill);
     SUITE_ADD_TEST(suite, test_build_failure_missing_skill);
     SUITE_ADD_TEST(suite, test_build_requires_materials);
diff --git a/src/kernel/config.c b/src/kernel/config.c
index 481a68220..135df78c5 100644
--- a/src/kernel/config.c
+++ b/src/kernel/config.c
@@ -1097,6 +1097,7 @@ bool config_token(const char *key, const char *tok) {
 void free_config(void) {
     global.functions.wage = NULL;
     free_params(&configuration);
+    ++config_cache_key;
 }
 
 /** releases all memory associated with the game state.
diff --git a/src/kernel/config.h b/src/kernel/config.h
index 8e0bd72e5..74565e25e 100644
--- a/src/kernel/config.h
+++ b/src/kernel/config.h
@@ -64,7 +64,6 @@ struct param;
     int lovar(double xpct_x2);
     /* returns a value between [0..xpct_2], generated with two dice */
 
-    int distribute(int old, int new_value, int n);
     void init_locale(struct locale *lang);
 
     int forbiddenid(int id);
diff --git a/src/kernel/config.test.c b/src/kernel/config.test.c
index a5bad30c7..c8fc84a1a 100644
--- a/src/kernel/config.test.c
+++ b/src/kernel/config.test.c
@@ -198,6 +198,8 @@ static void test_config_cache(CuTest *tc) {
     config_set("hodor", "0");
     CuAssertTrue(tc, config_changed(&key));
     CuAssertTrue(tc, !config_changed(&key));
+    free_config();
+    CuAssertTrue(tc, config_changed(&key));
     test_cleanup();
 }
 
diff --git a/src/laws.c b/src/laws.c
index 197433bfa..19078353e 100755
--- a/src/laws.c
+++ b/src/laws.c
@@ -776,6 +776,8 @@ void demographics(void)
     region *r;
     static int last_weeks_season = -1;
     static int current_season = -1;
+    int plant_rules = config_get_int("rules.grow.formula", 2);
+    const struct building_type *bt_harbour = bt_find("harbour");
 
     if (current_season < 0) {
         gamedate date;
@@ -793,11 +795,10 @@ void demographics(void)
             /* die Nachfrage nach Produkten steigt. */
             struct demand *dmd;
             if (r->land) {
-                int plant_rules = config_get_int("rules.grow.formula", 2);
                 for (dmd = r->land->demands; dmd; dmd = dmd->next) {
                     if (dmd->value > 0 && dmd->value < MAXDEMAND) {
                         float rise = DMRISE;
-                        if (buildingtype_exists(r, bt_find("harbour"), true))
+                        if (buildingtype_exists(r, bt_harbour, true))
                             rise = DMRISEHAFEN;
                         if (rng_double() < rise)
                             ++dmd->value;