What Beauty Products Do You Use Until the Last Drop?

I saw this question on Allure.com and it got me thinking - I buy so many products. Like, lots of them. Certain things I get tired of and only use a few times. Other things that I LOVE I will scrape out of the jar/tube like my life depends on it.

Here are my scrape-the-bottom-until-there's-nothing-left products:

1. Foundation or base - I'll confess, I hate buying foundation. It's not fun or interesting, it's more of a necessity. Therefore, I use up every last bit of it!
2. Mascara - I use my Haute & Naughty mascara from MAC every day. When I ran out a few weeks ago and was forced to use a few others I had laying around, it was torture. If you're used to your lashing looking a certain way, then you start using a mascara that just doesn't do it for you, it's miserable.
3. Primers - whether it be the UD Primer Potion, or the MAC Prep + Prime face powder, I always find myself replacing them once they run out. Priming in my mind is necessary if you want your makeup to last longer!
4. Eyeliner - black eyeliner (accompanied with a different eye shadow and mascara each day) is my go-to look most days. Replacing it is a must.
5. Face toner & Makeup Remover - Again, not the most fun beauty products to buy, but I can't get by without them.

On the flip side, doing this little list made me think of all the products I DON'T use up. All the eyeshadows, lipsticks, glosses, perfumes, etc that I buy and just sit there after I tire of them. Of course, every beauty product you buy won't be ideal or perfect - that's the fun of trying new things. But I do feel like my makeup cabinet is somewhat of a beauty graveyard in a way. I know, kinda morbid but MOST things I buy I don't use up.

So what does that mean? I'm going to try and not buy as many things. I know, my heart is racing too at the thought of LESS makeup, but i'm going to make a conscious effort to only buy something if I'm in love with it.

What do you guys think, what products do you always use up? Also, what products do you never use up? I'd be interested to see if your answers are similar to mine! <3