There is yet another option when deciding how to manage your paints during a session. The Wet Palette. Basically what it does is keep your paints moist for a long time, so you no longer have to worry about the biggest downside of a dry palette – paint drying out and changing consistency mid-session.
They’re easy to construct and can be made with just a few cheap things from around the kitchen. You just need some sort of plastic tray or re-sealable container (not too deep though). Put a thin kitchen sponge or even some soaked paper towels in the bottom, with a sheet of parchment paper on top. The bottom layer slowly feeds water to the drier top layer which in turn feeds the water to the paint sitting on it.
You get all the benefits of a dry palette, then add easier cleanup since you just toss the little paper top layer from the palette. Extended painting sessions on the same mix of paint. You can get up and go do something for a few minutes without fear of your mixed paint drying out. Some people have even been able to keep paint good for days and sometimes week if the palette is sealed and stored in the fridge, making it possible to mix one large batch of color to use on an entire set of models.
The chief downside is that it does cost a little more money. The parchment paper will also get used up, but not quickly making the cost practically incidental for maintaining the palette. It can also be a little tricky at first getting the right amount of water in the palette so your paints don’t get dry or gummy while not turning them into a diluted muddy mess.
Wet Palettes are the most difficult to learn to use, but once you get the feel of it the benefits are very nice indeed.