I only use a belt for deads, and that's because I went without once and really jacked up my back. That's a good question and I think you'll get varied answers ranging from "always use them to be safe" to "if you need the belt to lift it, that's not your max."
Originally Posted by He-Dan Harrison
If you got the quads, you can beat the odds.
Best Lifts: Gym, Contest
Bench: 325#, 315#
Deadlift: 521#, 510# trailer
Clean and Press: 220#, 175*5 axle