Castelli's bibs aren't known for their durability.

I ride 12,000 miles per year and do bike laundry once a week. I get about 3 years out of my shorts. They start out as my preferred shorts, then about a year in I'll mainly use them on short rides. By the 3rd year they're probably relegated to winter use because of the buttcrack window.

I've never actually had a chamois go bad on me. It's always the rear wearing through.