Chad Wesley Smith of Juggernaut Training Systems answers 7 common questions, great info!
A: Belts and other supportive equipment can have a valuable role in your training, but training without it can also be valuable tool to build the body. Training without a belt will help you ‘build your own belt’ of strength and muscle through the midsection but you can’t train beltless for a whole cycle and expect to hit a belted PR as soon as you add the belt back in. Within the context of a 12 week training cycle for a lifter who competes in belt and wraps, I would dedicate the first 3-4 weeks towards beltless training and higher frequency squatting. The next 3-4 weeks would be for belt only training and slightly decreased frequency and then the last 3-4 weeks would be dedicated to full equipment and the lowest frequency/highest intensity. Not using a belt during higher frequency training is the best option because it will reduce your output capability. The belt will cause the limiting factor of your lifts to be your back though, so to ensure that your legs are provided with enough stimulus to improve you must reintroduce the belt to use heavier loads. Take times in the off-season to work without equipment and build your body and as competition approaches become more specific and use your competition equipment.