At the end of the day, it is a fighter's choice to continue taking matches, and nothing should stop them from doing so. They are grown men, and it is up to them how they want to lead their lives.
There are mixed martial artists who will stay too long and damage their bodies and minds while they try to climb back to the top, even after they are past their prime.
But what is a fighter's prime?
Most would say it is the early to mid-30s, but Randy Couture proved that isn't always the case. Anderson Silva is approaching middle age quickly as well and hasn't shown any weaknesses or flaws.
A prime is something that varies from fighter to fighter.
Each fighter has a different time when they need to step back and realize that their time is past, but it is difficult for any man to know when that is.
Most fighters, especially on the highest level, never lose their passion for their job. They love training for every fight and want to keep going.
When an martial artist loses his passion, it is easy to slink off into the distance and move on. Their heart isn't in it anymore and that means that they are going to start losing. There are other ways of making money that don't involve getting punched in the face.
People like Tito Ortiz and Ken Shamrock who never lose the love of competition face a different challenge and a harder choice. They have to turn away from the job that they take pride in and find something new to do.
Ortiz has lost his last two fights in the Octagon, but is asking for one last chance to show that he isn't washed up.
Shamrock has been on an incredible losing streak, yet he continues to fight because that is what he is known for.
It is hard for them to pull away, especially on a losing streak because fans and fellow fighters see them as being at the bottom of the heap.
They need the win.
Need is a dangerous word. When someone needs something, they become immersed in it to the point where friends, family, health and happiness become second. They have to prove to themselves and every one around them that they are the best.
They need to make it back to the top.
Every loss can be blamed on the right circumstances not being presented to them and the next time will be different. They keep chasing that elusive win and after a while, that is all they see.
They train and focus on their next opponent because that fight will turn it around for them. If they can just get the big win, then the next will be easier. That is rarely the way it turns out.
There is no set age for when a fighter should retire, but there is a set mentality. When a fighter starts losing fights and needs to win the next one to prove they aren't over the hill, that is when they need to move on.