I mean, by the time I've painted for 5 minutes I've got the stuff everywhere, and I'm not happy unless I'm washing out the brush in between colors. I've been airbrushing for about 20 years, and I would still prefer to have a sink handy when I'm painting. There are a couple of ways to negate the sink, however. An airbrush per color is helpful, but not always possible. We keep a couple of bottles of water or cleaner on hand for rinsing between colors.
Baby wipes are helpful, also, for the extra drips and overspray.