Each species seems to have different life spans. None of which seem to be "short", say 2 years or less.
I would strongly agree with a previous poster in that these animals are not "delicate" but instead are very specfic in their needs.
There is no standard for pet stores to meet when it comes to their level of knowledge, more often than not a pet store thrives off of its location combined with its selection instead of people knowing the products or animals. Quite sad really.
I've had Chameleons live 7+ years that were adult size when I obtained them. Hope that helps