I've used Humbrol paints for years; and I work with MANY paint brands in my hobby (some are vintage, but excellent-), and there's nothing worse than opening up a favorite color...and finding a jar of paint mud in the bottom. Also, one day you may have to thin colors to make a wash or to mix/airbrush a bottle paint: using any old thinner...can spell DISASTER. Unless you have a degree in Chemistry (and research on specific paint formulas-) it's easier to have enough of the EXACT thinner for your paint(s) around...especially BEFORE you need them.

A great thinning solvent it works with of course humbrol and revell little tins to both air paint and for small details.