Alan Belcher is one of the few fighters to have walked away from MMA while still being very much in his prime. The former UFC middleweight contender closed out his career at the age of 29 after fighting Michael Bisping, who would go on to become champion, back in 2013 in the co-main event of UFC 159. He lost a technical decision to Bisping that night in New Jersey as he suffered a nasty eye poke that ruled him out of the bout. Belcher was on a four-fight winning streak and 6-1 before losing decisions against Bisping and Yushin Okami
More here: