21+ year old horses

What do you do with your 21+ year old horses ? I know they can still attend school rides but I feel it would annoy me to no end to see my retired horse getting extra stats, knowing that they cannot be in utilised in any way. It just seems I may be tempted to stop caring for them and let them go after 5 days...

Do you school your retired horses and don't mind the stat gain which cannot be used in breeding any more ? I'm just curious.

I school my retired horses because I can only really gain from it. A little extra income is fine by me. As for the stat gain, it doesn't bother me too much. I don't feed the elderly horses treats or anything, and they aren't getting that many stats from riding schools, so why care? Same with geldings if I get any.