My teeth are pretty sensitive so I was apprehensive to get them whitened. I decided to start with 15 minutes and if it didn't hurt continue from there. 45 minutes later I had a much whiter smile and no sensitivity or pain. To maintain my teeth a maintainence item came with my package, I can go in for a touch up whitening whenever I want at any location for free! I send all my friends and family in, great results and great prices!