Well it does seem that we may care about whiten our teeth to the point of over kill. Just brush your teeth twice a day with toothpaste use the kind that has whiting in it if you like.
Unless you are going to make a life stile change it is not worth spending money getting them white by buying expensive products or beaching at the dentist. Whiting you teeth does not keep them white you need to stop doing all the things that stain them in the first place.
Stop drinking any thing that can stain your teeth coffee, tea, soda etc. Also you would need to brush right after eating and no smoking. If you don’t change what you are doing to stain them in the first place, it would be like dieing you hair every time your roots grow in.
And whiting your teeth that much will in the long term do more damage.