How long will my teeth stay while after bleaching?

Depends on you: Bleaching really should only be considered a couple times a year at the most. If you take good care of them, brush and floss well and avoid staining foods they should stay white for a good while.

Depends: It depends on the speed they lightened, the chemistry used, your original color (gray vs yellow vs brown vs green), your final color, the individual structure of your teeth and your eating and drinking staining foods after finishing the bleaching procedures.

6 months - 2 years: I depends on your diet, amount of coffee, tea, red wine, etc. Bur generally from 6 months to few years.