I find that either the chamois starts degrading in some way, the waist gets funky, or, for some styles, they become kind of see-through in places where you don't want that!
I don't expect shorts will last forever. Nothing does. Some last 2 years, some last 4-5. I wore Terry Bellas exclusively, until when I went on my trip to Spain and they were too hot for the desert climate. Now I wear Sugoi RS Pro shorts most of the time, saving the Bellas for only shorter or colder rides, with my leg warmers (they have more compression). These shorts cost around 100.00, sometimes I can get them on sale. So, not the most expensive, not the cheapest. All I know, is that I don't fool around with shorts and comfort. I had to search to find 2 brands that worked for me, and at that each only work in certain conditions.
I also have some liner shorts, mtb shorts, skorts, cycling pants/dresses, and capris, so I can rotate what I wear. I don't wear my regular shorts for my short commute to work, instead wearing the other things in above sentence.
I also throw out at least one jersey a year, sometimes 2. I usually buy one new one a year. Last year, I through out a bunchI had had since 2005.