Those older horses can be so awesome. I have a 27 year old mare that we just love to pieces. She has always taken excellent care of my daughter on the trails. When every horse is acting crazy, she will be standing there looking at them as if they are a bunch of idiots. If there ever comes a day that she has to have bute to be ridden, then we will retire her.
Definitely pass on the horse you are looking at, but don't let that cause you to skip other older horses.
PITT BULLS ARE NOT THE ENEMY. WE ARE THE ENEMY. Shorty Rossi