Are you buying from a store or a private person? What do they feed him, how often, what lighting system do they use [no uvb lights and he may have mbd]. Does he have a medical history, any issues with parasites, bruses or breaks, eye issues. May want to see him eat a cricket or two, is his tongue shoot ok? Hold him, if he's scared and runs thats probably a good sign. Is his grip strong? Check his cage, if its roomy, clean with proper lighting and dripper, mister you know the owner cared enough to ensure a health enviornment for the cham. Good luck their great pets.