when do i change it some tell me when it starts to clog and overflow :stupid: :stupid: :stupid: :stupid: :stupid: :stupid: :stupid: :stupid: :stupid: :stupid: :stupid: :stupid:
Depends on what type of filtration and filter you have.
I definately wouldn't wait until it overflows, if you mean a HOB. That means it's way too late. You want to change it before it stops working, not a while after it does.