Do I Need A Make Up Primer?

I hear so much about make up primers, are they worth buying?

A make up primer is designed to temporarily smooth your skin. It usually contains silicones & polymers which create a smooth surface and waxes which bind with your make up to give it longevity. Not everyone needs a primer. Make up primer is really suited to those who have uneven skin texture (perhaps due to old scars) since they level out the skin. Its also helpful for those whose lip colour feathers due to fine lines or who find that their eye shadow creases easily. From my own experience I have found that after I have used a make up primer it does make application of foundation particularly easy. It just seems to prep the surface of the skin but as for adding longevity to your make up, I'm not convinced!