Your essential beauty products

I spend a lot of money on beauty products. Majority of my money is spent on makeup, hair care, and body wash. It's a terrible habit to have because you're constantly battling to find the best product. I can't tell you how many times I have discovered my new favorite product, only to find something better. I have way too many half full bottles throughout my bathroom. There are only a few items that never change and I hold near and dear to my heart. These are my essential products.

What are your essential beauty products?
What are your must haves?
How long have you been using the products?