It really depends on why the breeder is breeding. For meat, I would think the breeder would keep the does as long as possible, no reason to get rid of them. For show, keeping a doe too long creates a bottleneck.
I started with older does, and they still had big litters for me. The first 2 were three years old. I kept them for a year and culled because they out produced themselves. I have an 18 mos old doe now, and I have a 6 mos old doe from her and a jr litter of 3 keepers. There is basically nothing wrong with the doe, but for lack of space I would sell her if I could, because I no longer need her genetics. She was good enough to breed or I would have culled her, had two litters of 10 back to back and the last litter of 5.
I wouldn't give anybody crappy does, but some people would. I wouldn't take anything over 3, and it would have had to have had a litter within the last 3-4 mos. The ones I got all came bred and delivered successful litters.