Haven't we all experienced this scenario: a few hours after makeup application we see our reflection in the mirror and say to ourselves, "Where has my makeup gone??" Primer is supposed to be the solution to that problem. Primer has always been a mystery product to me. Does it REALLY work? Is it really worth the money? Every makeup artist I've spoken to suggests using it. The point is to provide a smooth surface for foundation application and to keep the foundation on. So...I decided to perform a trial of my own. I applied primer to one side of my face but not the other. I applied makeup exactly the same way on my entire face. I am now completely sold on the benefits of primer! Immediately I noticed my pores were not as noticeable on the primer side and I looked a bit more luminous on the primer side. I checked my makeup at two hours and four hours post application. At two hours after application there was a noticeable difference on the side of my face that had primer. I actually still had foundation left on that side! At four hours, the difference was less noticeable.