diff --git a/helpers.lua b/helpers.lua
index a1e423c..7f383ea 100644
--- a/helpers.lua
+++ b/helpers.lua
@@ -1,17 +1,23 @@
 local gfind = string.gmatch or string.gfind
 
+local expansion
 ShaguTweaks.GetExpansion = function()
+  if expansion then return expansion end
+
   local _, _, _, client = GetBuildInfo()
   client = client or 11200
 
-  -- detect client expansion
+  -- detect client expansion once; the client build cannot change during a
+  -- running session, so repeated helpers don't need to query it again.
   if client >= 20000 and client <= 20400 then
-    return "tbc"
+    expansion = "tbc"
   elseif client >= 30000 and client <= 30300 then
-    return "wotlk"
+    expansion = "wotlk"
   else
-    return "vanilla"
+    expansion = "vanilla"
   end
+
+  return expansion
 end
 
 ShaguTweaks.GetGlobalEnv = function()
@@ -84,32 +90,31 @@ ShaguTweaks.HookAddonOrVariable = function(addon, func)
   end)
 end
 
-local hooks = {}
 ShaguTweaks.hooksecurefunc = function(tbl, name, func, prepend)
   if type(tbl) == "string" then
     prepend, func, name, tbl = func, name, tbl, _G
   end
 
-  if not tbl or not tbl[name] then return end
+  if not tbl or type(tbl[name]) ~= "function" or type(func) ~= "function" then return end
 
-  hooks[tostring(func)] = {}
-  hooks[tostring(func)]["old"] = tbl[name]
-  hooks[tostring(func)]["new"] = func
+  -- Capture each hook's state in its own closure. The old implementation keyed
+  -- shared state by tostring(func), so reusing the same callback for another
+  -- hook could overwrite the first wrapper's original function.
+  local old = tbl[name]
+  local new = func
 
   if prepend then
-    hooks[tostring(func)]["function"] = function(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16)
-      hooks[tostring(func)]["new"](a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16)
-      return hooks[tostring(func)]["old"](a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16)
+    tbl[name] = function(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16)
+      new(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16)
+      return old(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16)
     end
   else
-    hooks[tostring(func)]["function"] = function(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16)
-      local r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14, r15, r16 = hooks[tostring(func)]["old"](a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16)
-      hooks[tostring(func)]["new"](a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16)
+    tbl[name] = function(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16)
+      local r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14, r15, r16 = old(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16)
+      new(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16)
       return r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14, r15, r16
     end
   end
-
-  tbl[name] = hooks[tostring(func)]["function"]
 end
 
 local sanitize_cache = {}
@@ -446,4 +451,4 @@ ShaguTweaks.GetItemLinkByName = function(name)
       return CacheItemLink(name, hyperLink)
     end
   end
-end
+end
\ No newline at end of file