How often should I change my skin care products?

I am using Clinique line for over 12months. I was wondering after a certain time is the product not anymore effective as it was in the beginning?How often should I change my skin care products?
If the product is continuing to work for you then theres no need to change to a different product. Our skin has a memory and if you change soaps or anything it will know and you can actually have irritated skin or even blemishes from switching until you're adjusted all over again- so if clinique is still working for you, thats great and you're lucky to have a product you like. Use it as long as you can!How often should I change my skin care products?
The general rule is that products expire after a year so you might want to toss those out and get new ones. Also Proactiv works well too and comes with a handy expiration date.
if u like wat ur usin then theres no need to change it unless its not helpin or it got expired