Although not so prevalent like back in the day, you do still tend to see those guys in the gym wearing the weight belts for their entire workout. A weight belt help to keep your core tight and stable. The good news is that it works, and well that is the bad news as well. Wearing a weight belt all the time or often will cause your core to become weak and dependant on the belt itself. A weight belt only really need to be worn when doing near maximum lifts. In the long run stay away from the belts and start improving your core!