My girls have a 30 year old gelding that they share. He came to us in rough condition but is now looking great. He has no real usable teeth so he gets his nutrition from a mash of senior feed and beet pulp along with a little Ultimate Finish.
He does get a little winded on a trails after about 1 hour. He will still pick up the trot and lope for them but we try to stick to mostly a walk for him.