Most people usually pay a lot of money for teeth whitening for cosmetic and psychological reasons. Most of the time, the effect of whitening is supposed to be permanent, especially when you get it done by a qualified dentist. However, you still need to keep in mind the fact that there are times when your teeth might stain again. In such cases, you would need to get the whitening done afresh, something that will cost you even more money. Some of the things that can result in this include:

Cigarette smoke contains tar and other substances which stain tissue. The fact that such stains are very difficult to remove is the main reason why most dentists charge a lot in order to whiten teeth that are stained as a result of smoking, and also advise clients to stop the habit in order to maintain the white teeth. If you have to smoke, it would be a better idea for you to use electronic cigarettes since these don’t contain tar, which in turn means that your teeth are likely to remain white for longer.
Drinking too much coffee
If you are an avid coffee drinker, you might have to choose between white teeth and the coffee. Coffee also has a reputation for staining teeth, as is the case with cola. You might have to think about having to stop drinking coffee if you are to retain the whiteness of the teeth.
Not brushing regularly
This is one of the commonest reasons why recently whitened teeth start staining again. After you get the procedure done, you should always make it a priority to not only brush your teeth regularly, but to do it well. You need to spend at least thirty seconds on each quadrant of the mouth, and also floss the teeth as well to be assured that they will remain clean and white.