diff --git a/build.cpp b/build.cpp
index 42ce563..a70384d 100644
--- a/build.cpp
+++ b/build.cpp
@@ -1,4 +1,5 @@
 #include "build.hpp"
+#include <unordered_set>
 
 std::filesystem::path OBJ_DIR = "obj";
 std::filesystem::path INC_DIR = "inc";
@@ -75,32 +76,23 @@ int compile_src_dir()
   nob_directory src_dir = get_all_files_in_dir(SRC_DIR);
   nob_directory obj_dir;
 
-  for (auto &&i : src_dir.files)
-  {
-    std::filesystem::path tmp = i;
-    obj_dir.files.push_back(OBJ_DIR / tmp.replace_extension(".o"));
-  }
-
   for (auto &&i : src_dir.dirs)
   {
-    obj_dir.dirs.push_back(OBJ_DIR / i);
+    std::filesystem::create_directory(OBJ_DIR / i);
   }
 
+  std::unordered_set<std::string> modified_heders;
+
   nob_directory inc_dir = get_all_files_in_dir(INC_DIR);
   for (size_t i = 0; i < inc_dir.files.size(); i++)
   {
     if (check_if_rebuild(inc_dir.files[i], BUILD_FILE))
     {
-      clear_build_dir(true, false);
-      break;
+      std::string heder = inc_dir.files[i].string().substr(4);
+      modified_heders.insert(heder);
     }
   }
 
-  for (auto &&i : obj_dir.dirs)
-  {
-    std::filesystem::create_directory(i);
-  }
-
   command.clear();
   command.push_back(cpp_compiler);
   command.push_back("-c");
@@ -118,12 +110,31 @@ int compile_src_dir()
   command.push_back("-Werror");
 
   int build = 0;
-  for (size_t i = 0; i < src_dir.files.size(); i++)
+  for (auto &&i : src_dir.files)
   {
-    if (check_if_rebuild(src_dir.files[i], obj_dir.files[i]))
+    std::filesystem::path tmp = i;
+    std::filesystem::path out = OBJ_DIR / tmp.replace_extension(".o");
+    bool reb = false;
+    if (check_if_rebuild(i, out))
+      reb = true;
+
+    if (!reb)
     {
-      command[src_loc] = src_dir.files[i];
-      command[obj_loc] = obj_dir.files[i];
+      std::vector<std::string> incudes = get_includes(i);
+      for (auto &&j : incudes)
+      {
+        if (modified_heders.find(j) != modified_heders.end())
+        {
+          reb = true;
+          break;
+        }
+      }
+    }
+
+    if (reb)
+    {
+      command[src_loc] = i;
+      command[obj_loc] = out;
       if (!nob_cmd_run_sync(command))
         return -1;
 
diff --git a/build.hpp b/build.hpp
index 4633124..a8605b4 100644
--- a/build.hpp
+++ b/build.hpp
@@ -1,12 +1,11 @@
 #include <cstdio>
-#include <cassert>
 #include <cstring>
-#include <ctime>
 #include <thread>
 #include <vector>
 #include <string>
 #include <list>
 #include <filesystem>
+#include <fstream>
 
 enum class Color
 {
@@ -81,7 +80,7 @@ bool nob_cmd_run_sync(std::vector<std::string> &arguments)
   return std::system(command.c_str()) == 0;
 }
 
-bool check_if_rebuild(std::filesystem::path &org_path, std::filesystem::path &new_path)
+bool check_if_rebuild(const std::filesystem::path &org_path, const std::filesystem::path &new_path)
 {
   if (!std::filesystem::exists(org_path))
     return false;
@@ -155,3 +154,24 @@ nob_directory get_all_files_in_dir(std::filesystem::path directory_path)
 
   return dir;
 }
+
+std::vector<std::string> get_includes(const std::filesystem::path &path)
+{
+  std::vector<std::string> ret;
+
+  std::ifstream ifs(path);
+  std::string line;
+
+  while (std::getline(ifs, line))
+  {
+    if (!line[0] == '#' && !line.empty())
+      break;
+
+    if (line[line.size() - 1] == '\"')
+    {
+      ret.push_back(line.substr(10, line.length() - 10 - 1));
+    }
+  }
+
+  return ret;
+}