Tubby is 16 1/2 and has never had his teeth cleaned in his life. He only gets hard food except for the occassional canned food as a treat. He has horrible breath, but the vet said his teeth look fine and he wouldn't recommend a cleaning for him.

I would say to ask the vet about it. If he/she feels that Houdini's teeth really need to be cleaned, then figure out how it should be done, but it's entirely possible that it's really not a problem and you don't need to risk the anesthesia at all. But I think your vet should be the one to make that decision since he/she would best know Houdini's risks and the benefits from the cleaning. Good luck!