When selling at the local arts & crafts fair, I usually post an offer to buy back or exchange any of my photographs in saleable condition for any reason. So far no one has chosen to to this. Also, on the back of framed prints is a lable that says something like:
Printed on an Epson 3800 with Ultrachrome
K3 ink on Epson Exhibition Fiber Paper.
Print life displayed under glass is estimated
by www.wilhelm-research.com to be 90 years
before noticeable fading occurs.
In a small market where most people know me, this kind of customer service seems reasonable.