I think this is based on trial and error b/c everyone's skin is different. Frankly I'm not into paying mucho $$$ so I use CeraVe. You get a lot of bang for your buck:
http://www.dermstore.com/reviews/product_Facial+Moisturizing+Lotion+PM_32780.htm
I'm 41 and regularly am mistaken for early 30's.