My belt is on during squats, deadlifts, bent-over barbell rows, and shrugs. Never on during bench-presses or leg presses. A belt does nothing on those exercises but restrict my breathing. If you're lifting heavy, that is the last thing you need. A belt is very important, however on any lift where the lower vertebrae of the spine are stressed. Who can lift anything with all of their discs hanging out of their rear end?