Confession: I don't love mascara.
For one, it's hard to find a paraben-free formula, which is a big issue. (Why? See my About Me). Also, I don't like waterproof formulas, as they tend to be an irritant to contact lens wearers like myself. And finally...I find that I don't love the effect enough to suffer through sticky or stiff or heavy lashes throughout the day - or the smudging! - and most formulas suffer from these drawbacks.
There are a few that I like, though, and I'll get to those some other day. However, no matter what mascara I'm wearing, I always wear a primer. While I don't think lash primers are necessary for everyone, I personally have a smudging problem with most mascaras. The primer nicely eliminates this problem, and I think it makes for easier mascara application, since your first swipe through is with a nice colorless formula. Priming my lashes allows me to go through my lashes once and prep them for mascara application, which is always a bit tricky; I've definitely poked myself in the eye before (mascara on contacts! Tragic) or accidentally applied mascara to my eyelids instead, in an attempt to get closer to the roots. It seems like mascara sticks better to primed lashes, and I don't get smudges at the end of the day. Sometimes I also just swipe on the primer after curling my lashes, if I want just a little bit more volume or I want the curl to hold all day. This is what I use:
Smashbox's primer is paraben-free, so I've made the switch (previously I was using Clinique's lash primer, which was a few dollars cheaper and just as effective; alas, it is not paraben-free) and I'm happy. It's $16 for 0.16 oz, which lasts quite a while, though I don't wear mascara every day (once a week, at most, or for date nights/etc). If you have smudging issues, or need a little extra volume, this might be the thing to try.