I've had quite a few different chams, although it's hard to say how old some of them actually were when they died.
Male Jackson's (adult when I got him): I had him for 7 years, and he just slowed down in the last month or so and I found him dead one morning.
Male Jackson's: 13 years, died of an infection that spread to the bone.
Female Jackson's: 6 years old when she died of kidney disease (from too much supplementation - I was young and stupid)
Male panther (adult when rescued, and in bad shape): 4 years, died suddenly of unknown causes
multiple
R. brevicaudatus: about two years each - I assume that's just about their natural lifespan
Male
C. quadricornis (adult when I got him): 5 years, sudden death from unknown causes
Female
C. quadricornis (adult when I got her): 4 years, was euthanized after getting an infection in the jaw (her mate stopped eating after she left, and he died just a week later)