I don't have many fancy bibs. My Pearl Izumi bibs (~$80 type) have lasted a few years with regular washing. The chamois in the Black Bibs fell apart after about 10 washings (they did replace the first pair, but it happened again, so I just moved on). DHB cheapy bibs are holding up okay after a few dozen wears; a custom club kit from HyperThreads feels about like the DHB in terms of quality, and had also held up without special treatment.

I was recently spoiled with some wool bibs. Pricey, but the fabric is noticeably thicker than most ... it feels like wearing actual clothing instead of paper thin spandex. Since I can't really afford to replace them, I only wash on delicate, dry on low, and pull them out before they're totally dry (and hang them to air dry completely).

When I'm at home, I'll usually wear each kit once before washing. But I also know from Touring that a little air drying between uses, a bit of hand washing the chamois as necessary, and my kits can go days without a full wash.