LOL... ok, lets not go there, but since when does tanning cause skin cancer? Let see, we have lived under the sun for how many years and in the past 20 years it has become evil? I am sure we can debate for YEARS on this one, but I always tell people to show me just ONE study that proves, not speculates, and I will shutdown the salon.... Now, burning, thats a whole other ball game and there is evidence that burning damages the RNA/DNA which means a high risk for cancer causing damage. (off soap box)
As for aging. Yes it can, but lets not confuse INDOOR tanning with OUTDOOR. Outdoor = UVC, UVC = damage to organic matter. UVC = nasty stuff. So outdoor tanning is not the best thing to do, indoor tanning, well: "Those who chose to tan should tan indoors since its a controlled environment". A LOT of people do both, even I do when I hit up Cancun for the weekend. But odds are those leather skins you see do a lot more tanning outdoors than in. I see MANY people on a daily basis, some have tanned for years and look great but I can pick out the ones who tan outdoors all too often. So based on heath, either indoor or outdoor is, for the most part, ok. It you are worried about appearance then tanning indoors almost exclusively may be best.
What can cause aging by tanning indoors is:
Frequency of tans. Three times a week is sensible to build a tan, once a week to maintain is also sensible. Go too often and your skin cant recover in time.
Lack of lotions. Lotion's first job is to hydrate the skin. Dry skin can easily result in the appearance of aging and wrinkles. Lotion is a MUST. We could go into all the lotions out there and which is best, etc... but I wont :)
Your eyes reflect your youth. WEAR those darn goggles! If you dont your eyes may reflect an older you.
Crap lotions: Crapy lotions do a crapy job
Outdoor lotions: Many of them contain mineral oil. MINERAL OIL is NASTY! By far the WORST thing, besides hydrochloric acids and polyester clothing, than you can put on your skin!
Lack of sleep. Really, this is a big one but not just for your skin!
What you can do it tan sensibly and use a good quality lotion. Get plenty of sleep and if your dont, use a daily
moisturizer for your body and one for your face that you apply after every shower. Oh and eat some beets to keep those eye colorful!
Thats my take on things anyway.