Skin Care Regime for 31 Yr. Old

Hi..was wondering about a skin care regime now that i have just turned turned 31. I usually only use Cetophil as a cleanser and Oil of Olay for moisturizer. But im wondering if should be adding something else to my daily routine. Is it necessary to start using those expensive creams that they have out and do they really even work? As far as lines dont have much of anything yet..maybe just slight lines between my eyebrows. Any suggestions would be helpful. Thanks!