I'm wondering how many of you out there actually mix your own paints. There comes a time when you just can't find the appropriate color from the manufacturers or you need a certain for highlights across an entire army - or like me you've come up with your own color for your army's base. See mine below -What I call OSH Khaki. This color is abouf 3 parts of VMC: Khaki to 2 parts VMC: Dark Sand. I use it as a base for all my Tau stuff.
Of course it's pretty important to have spare paint pots around. I would never recommend the older GW paint pots, but this newer generation certainly holds up. I seem to run out of Citadel washes. I use them so often and they also don't give you much per pot. Each pot is really only about 2/3 full when you buy it so chances are everyone has empty Citadel wash pots around. Wash pots are also good because it's easy to wash out the dried-up leftover washes from the rims of the pot and such.
It's important to record your ratios somewhere in case your going to mix more later. I actually measure out the paints in a separate container and pour it into these old pots. Then I throw in a penny to help mix it up. It never hurts to add a little water at this stage but don't over do it.
I've mixed up a couple of these. One for my Tau army, one for this Alpha Legion project (actually mixed up a big jar of it), an ogre flesh pot, and a color that combines Shadow Grey and Space Wolves Grey for painting Space Wolves and so on.
Of course, now that the whole range is completely different, I'll have to adapt to some new colors for this. It's not a bad thing, especially since an good friend of mine gave me all his old GW paints - here's to hoping I get to use them all before they dry out!