Is it necessary to purchase the serum along with the cream?

I just purchase this Dior HydrAction Rich Creme, so I wonder if I require to buy Dior Hydraction Serum??


here's the picture for both items





http://www1.macys.com/catalog/product/in… [the one i bought]





http://www1.macys.com/catalog/product/in…





Is it necessary to purchase the serum along with the cream?
its not neccesary, if u;v got the money then buy both, if not ... i always find cream is better. go to the dior counter n ask their advice if u want to kno more