Who are the wrestlers you think should hang it up due to injuries or age?

I say the Undertaker needs to hang it up. His body is more frail than a leaf. Every single month it seems like he comes up with a new injury he either has to cope with or take time off to heal. Triple H is another wrestler whose body has gotten more brittle with every match and every year that goes by. Scott Steiner shoudl consider hanging it up to. I am still amazed that the guy can still deliver a credible match in the ring as witnessed in his match with "The Freak" Rob Terry adn he is a lot more technically sound than most wrestlers today, but he can barely run, has trouble walking, can't do the standing "frankensteiner" anymore like he used to in his prime, and he can't even do a powerslam on someone as big as Rob Terry due to the bad shape of his legs and hip. Kurt Angle has about 3 more years left, but his age is beginning to show. Still, Angle is proving that despite his age he can hang in there. Sting should also consider hanging it up given that he has already hit the 50 year old mark and much of the wrestling maneuvers wrestlers do on him will likely put him in a condition similar to Hogan. I would really hate to see Sting suffer from a degenerative spinal condition like Hogan due to the punishment he suffers in the ring. Scott Steiner is already suffering the ill effects of years of wrestling. So who do you think should retire due to age or injury?