Hair getting used to a product

Hey there!

(First post, weeee!)

So, a lot of people change their shampoo/conditioner/etc. so that their hair doesn't "get used" to it (btw, anyone know why this happens? Just out of curiosity...). Do you change? If so, how often? And what products do you use?

I'm asking because I was thinking of buying some Redken All Soft, but I don't want my hair to get so used to it that it doesn't have any effect (especially seeing how expensive it is...), and was thinking of alternating it with Redken Clear Moisture (I think it's called that, can't actually remember at the moment ), like using the All Soft once/twice a week and the other one the rest. Any opinions? Suggestions?

Thanks!

Hmmm, yes a clarifying shampoo might be a good idea. Thanks!

As for bad hair days...I think we all have them, in need of a trim or not. I generally wake up looking like I have a blonde afro. Not the most coveted look ever 

I agree, I think some products, particularly those with silicones can build up.  At that point your hair starts to weigh down and look limp.  Using a clarifying shampoo would fix that, so maybe that's why people do it.