Do you wish your foundation lasted longer or looked smoother on your skin? Are you using a primer? If not, now is the time! Primers can help control oil, make your makeup last longer, and make your pores and fine lines less visible. The primer I use in my makeup kit on clients is Smashbox Photo Finish. I use the original clear formula. Basically it glides on the skin so that the skin appears smoother and helps foundation last. Smashbox now has many different formulas so that you can have oil control, cancel redness or add a glow.
A couple other ones to check out are Laura Mercier (once again many options to match your needs) and MAC (also lots of different types).
Some people use primers everyday, other people use them when their makeup needs to look extra polished for an event...just know that primers are something worth checking out!