Just a quick little tip
Every now and then I read about how people throw away their polish because it's gone bad, thick, goopy, solid or stringy. Of course we always like a good excuse to go out and buy some new colors, but in terms of sustainability it's better not to. So if you can, never throw out your nail polish.
What happens is that nail polish actually thickens up over time. This is caused by the evaporation of certain ingrediente. Some people add nail polish remover or even acetone to thin their polish, but that's a no go. When you're adding acetone you're actually breaking down your polish instead of thinning it. Adding thinner on the other hand, actually restores the previously existing and now missing element in your polish, making it a whole again. How spiritual does that sound! - Please forgive me for my corniness.
Different brands
I'm not sure if it really matters what brand thinner you use, I've tried several and liked them all. The brands I used are OPI, Mavala and as pictured: Seche & P2. I really like the P2 thinner because it's highly concentrated and really cheap. It does suck to have to travel all the way to Germany to get your hands on it though. If you're ever buying or ordering nail polish at a (r)etailer, have a look around, because a lot of stores do sell thinner!
With love, Michèle