MMA fighting is a hard hitting hitting, brutal, life shortening sport. It is one of the few sports where the occasional loss, isn't the beginning of the end for a competitor, as any fight can go either way. When too many losses are racked up however, it may be time for a fighter to consider hanging up their gloves. The people on this list have either been around the octagon too long, or have other problems that should be the reason for their retirement.

The sport of mixed martial arts takes a toll on people, and some fighters need to accept that retirement may be the best move they can make. It's hard to try to tell these warriors that they should retire. You really think they will listen to other people?

These people fight for a living, and it fuels their adrenaline, unlike what us normal people could imagine. Yes, it is unhealthy, but it's a means of getting paid, and some get paid a lot.

Take Chuck Liddell for example. At the end of his career, the Iceman would get knocked out very often. These knockouts were highlights, watched over and over, and Liddell could have saved himself a lot of trouble if he retired. Eventually, Dana White told Chuck it was time to retire, and he did, but it wasn't easy for Liddell, as it took some serious thinking.

Fighters often do not consider the long term effects of their careers, and are only fueled by competition. Fighters can develop brain disorders after retirement, or during their careers, which must be taken seriously. CTE is a brain disorder that can happen after any person sustains enough concussions, which for a fighter is common place. This isn't a debate about CTE or concussions though, this is a list about which MMA fighters and need to call it a day and focus on their future endeavors.

As always feel free to comment in the section below to let us know who we forgot, or who you don't agree with.

15 15. Quinton Jackson

Quinton "Rampage" Jackson would be higher on this list, if this were being written in 2013, but the former UFC Light Heavyweight Champion is actually on a winning streak. His last four fights have all been victories, either by the way of unanimous decision, or knockout punch. So in light of his most recent accomplishments, Jackson should go out on top, leaving a good memory in his supporters' heads. At 37 years old, "Rampage" may have one powerbomb left in him, but chances are if he dead lifts his opponent, he isn't getting back up.

14 14. Rashad Evans

In light of Rashad Evans being put to sleep by Glover Teixeira recently on UFC on Fox, it may be time for "Sugar" to call it a day. Evans had an excellent run during his career, rarely being hit with his fast and dodging style of fight. Though Evans only has five losses to his name as a fighter, his age is catching up to him, and his former speed that led to 19 victories in his career is disappearing...fast. At 36 years old, he's not going to get any better.

13 13. Tito Ortiz

Oh you didn't know Tito Ortiz was still fighting? Well maybe that is because the former UFC Light Heavyweight Champion has been getting rocked since 2006; only winning three fights since his Shamrock victories. Truthfully, it looked like Ortiz could make a comeback, winning his first two fights in Bellator, but those hopes were squashed after being chocked out by Liam McGeary in the first round of their fight in late 2015.  Ortiz should quit while he is ahead, and get of MMA before someone forces him to.

12 12. Kimbo Slice

Kimbo has never really been a serious contender in the octagon, but more of a draw for curious viewers. Since his "debut" on The Ultimate Fighter, fans wondered what kind of transition the former street fighter could make in the UFC. Slice found moderate success, having only lost two matches to date; both TKO to Seth Petruzelli and Matt Mitrione respectively. Slice's most recent match against former friend/crew member Dhafir "Dada 5000" Harris at Bellator 149 was the most lethargic fight that has ever been shown on television. Both men nearly died of exhaustion, and at 42 years old, Slice should retire from MMA.

11 11. Diego Sanchez

Diego "The Dream" Sanchez is already 34 years old, and he has been beaten up, and taken some rough beatings in his career. He has been a solid fighter throughout his career, but his career never amounted to real success. Everyone loves him for his style, and attitude, but it may be time for Sanchez to quit fighting, as he has lost more fights than he has won since 2009. Even though none of those losses were from knockouts, he still has lost six fights that a younger Sanchez would have won. It's time for "The Dream" to end, before it turns into an awful nightmare.

10 10. Kazushi Sakuraba

Everyone knows Kazushi Sakuraba's career has run its violent course, and it is clearly time to hang it up, and retire from the sport of MMA. I guess it is inspiring to see a 46-year-old guy still go at it in the ring, but also scary, and he shouldn't put his family in this position.

Sitting at a professional record of 26–17–1, Sakuraba has lost more than he has won during the past decade. Every fighter loses, but Sakuraba has been dominated during his losses, often being submitted, or knocked out.

It was nice to watch the Japanese fighter's career progress as it did, and as I say once again, his career has run its course. Did it go the way he wanted? I'm not sure, but he should be proud of his personal achievements for sure.

9 9. Stefan Struve

Fun fact about Stefan Struve: the Dutch fighter, is the tallest in the UFC.

He made his pro career start at age 17, and it has been a rocky road for him. Struve has an enlarged heart, which is a serious issue for him, and his fighting abilities. When Struve tried to return to UFC in 2014, he had a panic attack backstage, and his heart began to palpitate. It has been no easy road for Struve, and he should retire in my opinion.

Struve can control his condition now, but that does not mean it will always be that way. It is not helpful to be taking hits, and getting beaten to near death a few times a year surely won't improve his health.

Struve has been a good fighter to watch, and I'm sure face, but his heart condition scares me, in that one day it will go off, and he will never be in the same condition he is today.

8 8. Ken Shamrock

Ken Shamrock was the man to beat in the UFC in the early 90s, even bringing his "World's Most Dangerous Man" persona to the world of professional wrestling after stepping away from the octogan. When Shamrock jumped back into the world of MMA after wrestling, he was a different person than before, lacking the explosiveness he once had in the sport. In fact Shamrock, who was inducted to the UFC Hall of Fame, is actually only 4-12 since 2000, highlighted by his three-peat loss to Tito Ortiz. At 52, Shamrock may be fit to work security, but his days in the cage are numbered.

7 7. Anderson Silva

This guy has nothing left to prove, nothing.

Anderson Silva is for sure one of the greatest fighters the sport has ever seen, and ever will. With that being said, there is really no reason for him to continue fighting. Silva doesn't really need the money, and has plenty of endorsements. Despite nearly knocking out Michael Bisping during his last fight, we have to remember that Silva lost that fight, and also endured two brutal beatings from Chris Weidman.

It has been a fantastic and fun filled career for Silva, but Silva should think about moving on to a new endeavor. A fight with Nick Diaz would be interesting, but other than that we have seen all we need to from him.

Anyone agree?

6 6. Vitor Belfort

No one is questioning this guy's heart and passion for the sport, as Vitor Belfort is a fan favorite. At 39 years old, he has been around the fighting scene for quite a while. One of his best victories was a TKO against fighter Tra Telligman at UFC 12, in 1997. It also can't be forgotten that Belfort nearly broke the arm of Jon Jones at UFC 152. By the way, Jones was a light heavyweight champ.

This guy is a beast, and no one doubts that, and like other guys on this list this mention is more about age than achievements.

5 5. Josh Koscheck

Not everyone likes this guy, in fact he is hated many fans of MMA, with many people actually ordering fights just to see "Kos" get beaten up. Ironically even the haters of Josh Koscheck are concerned about the grappler, especially after suffering two knockouts from Robbie Lawler and Tyron Woodley; these both came in the first round, mind that. Koscheck has fought many battles, and has had a career that anyone would be proud of, so a career change may be the right decision before he takes any further beatings.

4 4. Mark Hunt

The New Zealand born mixed martial artist is already 42 years old, but Mark Hunt still hasn't showed any indication of hanging them up. Sure, in the start of his great career he was the opening match on the card for big events, but when he won the K-1 Oceania Title, people knew he was no joke.

This is behind him.

Mark Hunt is aging, no doubt about it. Though he is still performing at great levels, a retirement could be within reason soon. At some point, and it could be soon, he will brutally decline, which will be painful to watch for fans who have been fans of his.

3 3. Frank Mir

A true legend of the game, Frank Mir shows no signs of defeat...until he is being defeated. Mir has been in some of the most epic fights UFC has ever seen, but Mir has been on the losing end recently, and that comes with age. His knockout by Alistair Overeem was a huge blow to his career, along with his tough loss to Daniel Cormier.

He went 0-4, after these string of events, and being win-less in the UFC is a recipe for retirement. Frank Mir, fans thank you for an awesome career, but please save us the disappointment, and hang it up.

2 2. Dan Henderson

One of the Pride fighting legends, Dan Henderson is known for his unique strength. But at 45 years old, Henderson knows he is at the end of his career. A couple years ago, when he lost to Daniel Cormier, and went 1-4, things started going down hill for the grizzled veteran. And despite still using his most infamous weapon, which is a right hand punch called the "H-Bomb", it still may be too late in his career to turn things around.

It would be smart for Dan to really think about leaving MMA, as his health could start suffering from repeated shots to the head.

He doesn't need a UFC belt to prove his legendary status as a fighter. Everyone knows he is one of the greatest fighters of all time, and Dan should be applauded for his career and efforts for MMA.

1 1. Little Nog (Antônio Rogério Nogueira)

The twin brother of "Big Nog",  Antonio Nogueira is a legendary fighter, with "Little Nog" never having lost two fights in a row, which is crazy impressive. But at 39 years old, his physical stature is getting weak, and his body is failing on him. During a fight with Anthony Johnson, Nog was taken down in a minute, and it was absolute domination. It was actually hard to watch for the fans of Antonio. Painfully hard to watch.

Watching him take more beatings like this isn't necessary, or fair for himself. His ranking is still high, sitting at number ten among lightweights, but I believe it will fall soon.

Thank you for an awesome career LN, but a retirement would make the most sense at this point.