Im with Randy, I tend to work as long as the brain focus' is active. There are some days I will work and disover its way past time to find a pillow. Other days, I will stand at the bench and just fondle parts, thinking for an hour, then decide I just dont feel the love so will go do something else. Definetly a lesson learned from restoration work, if your not feeling it, you are better off just to go play cards or something, the time it takes to finesse what you goofed up isnt worth it.