Upon each invocation of the PHP application, Smarty tests to see if the current template has changed (different time stamp) since the last time it was compiled. If it has changed, it recompiles that template. If the template has not been compiled, it will compile regardless of this setting. By default this variable is set to TRUE.

Once an application is put into production (ie the templates won't be changing), the compile check step is no longer needed. Be sure to set $compile_check to FALSE for maximal performance. Note that if you change this to FALSE and a template file is changed, you will *not* see the change since the template will not get recompiled. If $caching is enabled and $compile_check is enabled, then the cache files will get regenerated if an involved template file or config file was updated. See $force_compile and clear_compiled_tpl() .