This free little application is good to have around if you forget to save or if you haven't activated autosave in your applications. SaveCircle allows you to set a countdown and auto save for you.The application offers two choices for auto save: every frontmost applications or the application of your choice. I recommend to leave it for every application as that way you need not worry about which one is saved or not.
Just slide the switch (similar to the Time Machine switch) to On to get SaveCircle running.Pressing File from the menu bar will allow you to modify the countdown by minutes or hours.
The countdown can appear in the application or be detached. Unfortunately there isn't any easy way to set it by seconds though.Most applications you use should have auto save running.