Should we use single toothpaste for whole life?

It does not actually matter really Sweetie, but I have been using the same brand of toothpaste for about 40 years now and my teeth are still white. Of course the manufacturers are continually improving the product, so there will always be some changes. In addition they also make many different types of toothpaste, and the biggest manufacturer of toothpaste is actually Colgate. I am not sure how many varieties they have available in your country, but there are about 10 of them here from what I have seen. :) It is up to you of course, but if you are happy with what you are using, why change? I will be seeing my dentist in a couple of weeks, so I will actually ask him and let you know what he says about whether it is important to change the brand from time to time. With things like shampoo and conditioner, they do recommend changing every so often or at least using a different brand once in a while. The reason for this is because of the build up that stays on the stands of hair but with a change, even once, it will get rid of the old stuff.

no i think its not improtant to change toothpaste i also used colgate last 2 years

I don't think it really metters what brand of toothpaste you use. As far as I know, toothpaste companies are always making their toothpastes better, so technically you are using a different toothpaste.