10 isn’t even middle aged yet for a horse. Horses in a domestic environment usually live to 25-30 years, sometimes even as long as 40 depending on breed. Most horses are still sound to ride well into their 20’s. Even with some mild arthritis most will still be fine for light riding since it’s good for them to keep moving, sometimes just needing a some maintenance like occasional joint injections to keep them feeling their best. Needing a dose of Bute (horsey Advil basically) before and after every ride isn’t normal though and tells me this horse is in a lot more pain than they seem to think. The whole “breaking their spirit” thing is a rather outdated notion in horse training these days. Yes there are certainly still people who take the term breaking in literally like that, but many are moving away from those sorts of training methods and more towards kinder techniques. There’s been a bigger audience towards positive reinforcement and consent-based training recently, though those methods are still more in the minority, even those using more traditional methods have been implementing more behavioral psychology and slow considerate training.