I use the weight belt on two occasiong, squats or deads at 6 reps or less. A friend at the gym says you should never use the belt cause its a crutch. He feels you'll build a stronger core by avoiding it. I feel more confident wearing the thing on my heavy squats/deads so I'm torn. What do you guys think?

I could care less about big numbers, I'm more interested in size. Belt or no?