24 hours and water-based!
I've been using the Mirenesse Secret Weapon mascara, in a brown color, for years. It's a little different to apply than the standard, but once you get used to running the tip of the applicator over the lashes before using the brush, there's not much else to learn.  It's easy to get a nice natural look, and since it's water-based it's possible to refresh it with a mist of purified water if it gets a little dry in the tube. It stays on well even through rain (as long as you don't rub your eyes), and still comes off easily in the shower with just water and minimal fuss. I've never tried to layer it for the heavy lash look, so I can only recommend it for a more natural look. And for that, it's truly the best I've found. And it outlasts other mascaras I've used previously, so the cost is easily justified.
Rating: 5 stars