I'm a smoker (still trying to quit) and a coffee addict, and had noticed my teeth getting yellow last year. I'm still in my 20's and haven't been a smoker for long so my problem wasn't severe, but I decided to deal with it, I thought of it as a motivational move to get me to quit smoking. So I went to a dentist not far from where I live and got my teeth bleached.
The whole process was extremely uncomfortable (8 on a scale of 1-10), my gums were very sore and my whole mouth felt dry and parched throughout the 45minute procedure, but after it was over, I loved how sparkly and white my teeth looked. Sure my teeth weren't that yellow to begin with, but they looked dull.
However, I'm sad to say that I never did quit smoking and my caffeine addiction is as strong as ever. My teeth have gone back to being dull and yellowed like they were before I bleached them (I have a feeling that if had I not gotten them bleached, they'd be alot yellower by now, so I don't really regret having done it), but I guess that's my fault.
I've decided to quit smoking for good and will be on Chantix soon, then after that I'm planning to get my teeth bleached for the second time.