Since you will be whitening as long as you have teeth... may as well go to the dentist, get a mold done, and take home the little rubbery plastic molds. Then, you can go in and get "refills" for the whitener whenver you need them. Maybe like 4x a year after that. Start up is the most money, maybe close to $300 or more... but the tubes are around $20, and you only need some of the tube every few weeks... In the end, you get teeth white the quickest (it's really quick!) and you can save money.