Originally Posted by NVFlinch

All my leather saddles (Brooks, Rivet, Gyes, Berthoud) were bought used. Only ever had one fail, and that was a cheap and cracked Brooks copy I got on a used bike.
Every saddles has a cutout, and I made a plastic slot template - several Saddles came without cutout slots and I cut them. Works peachy keen!

Tips 'O' the Day:
1. Check the leather for significant cracks, especially on the rear and nose near the rivets, and underneath. If any underneath cracks = reject it. If the saddle has a lot of recent oil or treatment on it, the owner m-a-y be trying to hide something, not always though.
2. Check the tension bolt carefully, as some/many pictures in ads have the bolt loosened to make it look like it was never tensioned (and usually way to much!). You can see the difference in wear on the bolt that sticks out from the nut if someone is trying to pull a fast one on ya.
3. Look for leather stretching/ovalizing at the rivets - generally this means that the saddle has been stretched too much or been wet a lot.
4. Bent rails, lots of rust (means wet)?
5. Is the saddle nosepiece and leather tilted or rotated a lot to one side? Not good.
6. Is the leather flaking off or checked excessively, especially underneath? May mean rotten leather.