I have not read most of this thread so forgive me if I’m commenting on something that has already been covered. Lots of people retire horses at a younger age, I should know since I have one of the better known retirement farms in the country. For horses that have been “big time” show horses (I don’t mean 4 or 5 small “A” shows per year or a few locals), they are often retired between the ages of 10-14. Often they could keep going, or step down to the 3’ and eventually down to the 2’6", but their owners don’t want that for them. They feel like the horses have done enough and now it is time for them to just enjoy being horses. Trust me they like it, they like it far more than “having a job” and they live long and healthy lives in retirement. Their job becomes being a horse and being a part of their group. That job becomes more meaningful to them than any work they ever did that involved a rider.
Obviously not everyone can afford to retire their nice but still riding/showing sound horse at a young age, or even if they can afford it they don’t want to spend the money. There is nothing wrong with a horse that can still physically and mentally handle being ridden continue to be ridden.
But it isn’t necessarily uncommon for people to retire their horses when they have hit a “peak” for whatever their career was/is. For some horses that was being the national champion for the second time, or winning the zones again, or having been a strong competitor at the Grand Prix level (jumpers or dressage), or winning a gold medal at the Pan American games. All of the above were accolades that some of our residents earned during their careers. Some of our residents were retired when they were older, and/or when soundness issues dictated they be retired. Some of our residents have owners that retired them in their early to mid teens while they were still sound. They felt the horses had given them their all for several years under tack, and it was time for them to give back to their horse - and they were in a financial position to do so.
The two youngest horses we’ve had arrive for retirement were both 7 at the time they arrived at our farm for retirement. Both had career-ending injuries and they were not going to be suitable for even light work under tack. Since they were so young both of them had owners that did everything they could to get them riding sound, they didn’t give up without trying hard and spending a lot of $$$$. The horses are definitely pasture sound, but not more than that. Not all retirees are old, or even close to old. We’ve had several arrive at our farm under the age of 10.