I'd only wear a belt for heavy lifts.
Wearing it elsewise hinders the stabilizer muscles from working and growing, as the belt is doing the stabilizing for you.
It kills me tro see people wearing belts the whole workout...even for chest..WTF do you need a BACK belt for to work your chest??
I've tried using a belt for bb rows and such, it just seemed to get in the way, and provided no help.
I only use mine for heavy squats. That's just me