Does changing your hair shampoo every week help more than changing your shampoo every 3 weeks?

I heard from a friend that when washing your hair it's good to change your shampoo one a week and another friend said every 3 weeks. Any ideas or answers????Does changing your hair shampoo every week help more than changing your shampoo every 3 weeks?
I work as a hairstylst and people ask me this all the time. Drugstore shampoos leave a wax build up on your hair each time you use them so when you switch to a new shampoo, the new one cleans off the build up of the old one. Thats what makes your hair feel better and softer. Im not saying that you shouldnt use those shampoos (actually i am but i know salon shampoo is expensive!) but maybe buy one bottle of a cleansing shampoo from a salon and use it once a week or every other week.Does changing your hair shampoo every week help more than changing your shampoo every 3 weeks?
No changing that often will not help. Your hair becomes kind of immune to one type of shampoo but that takes 8 to 12 weeks for that to happen. Try having two different kinds of shampoo and roatating them.
ok dont switch to using shampoos that are not for your hair type. two brands that i would suggest you use is paul mitchele (spelling may be incorect) and Biolage. these two companies are used mostly for salons and using it at home would work wonders on your hair. im 16 and im a very active person, i swim so shampoos like treseme, herbal esences, pantene dont work they harm your hair more than they do repairing. both of those brands that i have suggested may be a little pricey, but they have different lines for different hair types. IT WORKS TRY IT. dont switch shampoos unless its reallly necessary.
when i run out of shampoo, I use my bar of Dial Anti-Bacterial soap......
I heard that it has nothing to do with changing shampoos every so often. It just depends on your hair type and the type of shampoo that is best for it. I trust shampoos that come from salons than from supermarkets. There is only one supermarket shampoo that I trust and it is Treseme (spelling?) It works wonders on my hair and it is affordable.
nope, jus use whatever is best for ur hair type.
I think the best thing to do is use Neutrogena shampoo once a week. It removes any residue left behind by your shampoo.