Primers--You're Wearing WHAT on Your Face?

Primer is one of those beauty products that sounds like an enormous crock until you try it.  Then, suddenly, you understand why everyone is spending gobs of money on something that is invisible.  The Emperor DOES have clothes, and when they work they're awesome.

That said, some primers are absolutely not worth the money.  For the beauty newbie, here are a few things to keep in mind when you're deciding which primer to purchase.

• Smashbox is the heavy-hitter for facial primers, partly because it was the first.  
• Many, many beauty bloggers have talked about using Monistat anti-chafing gel (NOT the yeast infection treatment!) in lieu of Smashbox primer as it supposedly contains the same ingredients.  I haven't been brave enough to try it myself, but my skin is acne-prone and I'm always leery of new skincare products when the one I'm using works well.
• Urban Decay is the major eye primer brand--samples of Primer Potion are packaged with most of its palettes nowadays.  
• Both Smashbox and Urban Decay have undergone packaging changes in the last six months (Smashbox went from a pump to a tube and UD went from a little pot with a doe-foot applicator to a tube) and neither product is working the same way it once did for me.  More on that below.

The whole point of primer is to provide a layer between your skin and the product.  This layer will both prevent product from settling into your fine lines and pores (thus eliminating cracks and creases in your makeup as the day goes on) while also providing a grippier surface for the product to adhere to.

So, do they work?  Well, yes.  I started using facial primer (Smashbox, original formula) several years ago, and even though a 6 month supply was over $50, I kept buying it because it unquestionably helped my makeup stay on longer.  Even when I transitioned from mineral makeup to a tinted moisturizer I kept using Smashbox because it really worked for both types of foundation.  When I began using eye makeup more frequently I started applying Primer Potion (because it came with the Naked Palette) before my shadow.  I was so accustomed to using a facial primer at that point that I didn't balk at using something on my lids before applying a base color.  Like the original Smashbox, Primer Potion did exactly what it was supposed to: it kept my shadow from creasing, and it kept the product on my lids all day long.

Do they STILL work?  This is a somewhat tricky question.  There have clearly been formula changes, and they haven't necessarily been for the better.  The consensus on beauty blogs I read (and I can vouch for this myself as well) is that the formula of Primer Potion changed when they switched from the pots to the tubes.  I never experienced any creasing at all when I was still using my sample-sized pot, but have had issues with creasing (only when using my MAC shadows, oddly enough) in the last month or so since I bought the tube.  When I use roughly double the amount of product I used to there's no creasing, but any less and my eyes look like a hot mess by the end of the day.

As for Smashbox, I HATE the tube.  I find myself wasting a ton of product around the mouth of the tube, and the formula feels like it's separating when I squeeze it out.  I'm not seeing the same kind of chatter about this that I've seen about Primer Potion, so it could just be my bottle, but at $49 a pop I'm not likely to purchase another when my current supply runs out. 

Do you use primers?  Which ones?  I'm clearly in the market for something new, and imagine that I'm not alone in that wish.