Don't buy normal trousers belts, instead buy elastic belts which can last literally for life
(i5.walmartimages.com)
I can't tell from pictures, but I do not believe the belt in the picture is elastic. It looks like Nylon which isn't elastic and should last for a long time. It will wear out, but with care should last for a lifetime. I've seen elastic belts similar to the above, and those the elastic will get old and wear out in 10-20 years. Belts like pictured can also be made of other fibers (both natural and synthetic), that are not elastic. Some of them will last longer than others - it is important to know what the belt is made of, not just the style.