OK, I have a confession to make.
I have definitely come to the sorry conclusion that I'm just not a neat painter. In fact, truth be told, I'm really quite sloppy. It's a bit embarrassing. I'll watch other people I know who paint, and somehow, the pigments in their palettes always look so pristine and organized, vibrant and lovely to me. I'm in awe of them. I've never been able to do that.
Mind you, I have numerous palettes, because believe it or not, I am somewhat particular about them: I don't care for the plastic ones; I like metal Holbein-style palettes, but aside from that, my bad habits with them all are the same: I very rarely wipe off the mixing well areas after painting, because I admit that I kind of like it when the paints dry and make neutral grays and diffuse tints.
I just sort of dab whatever's there with water again, pick up some pan pigment, and have at it the next time. I don't care if there's been a green in that mixing well; if I want a pink, as long as there isn't a really dark stain left in the well, I just slap in a bit of alizarin crimson, or a magenta or something like a rose madder pigment mix in there, anyway.
I read, not too long ago, that Lucy Willis, one of my favorite artists, does that, and it made me feel better that someone as talented as Lucy had such idiosyncracies as well. (Lucy never sketches first before painting, but she always goes directly in with paint, and sometimes sort of "sketches" out a light image with those muted grays that are formed from old mixes, first.) She's amazing. I have found myself doing that same thing quite often lately, so it made me feel validated to read that she does so. When I'm finished, I do clean off my brushes, and put them safely away, but then I just close up the palettes with all the mess right there to greet me again the next go-round.
On some of my palettes, I shamefully admit that I don't even keep the pigments separate in separate pans. I mean, I squeeze tube watercolors two to a pan sometimes, in opposite corners, but sort of like twins, sharing the same room.
You can definitely see which paints I use the most, because they're the pans with big, gaping holes where vibrant pigments used to be. French Ultramarine is a definite favorite that I evidently reach for all the time.
I'm also not one of those people whose yellows are spotless and light--I always have dabs of green or blue or red somewhere in their midst. Same with my reds--I almost always find bits of blue there, where I've been mixing lavenders or purples. I figure, you never know what interesting tints might emerge from such serendipity, and besides, if I really must, I can always resort to spritzing a little bit of water on them, and dabbing them off a bit to neaten them up.
I don't really think people would know I have such bad habits if they didn't watch me in the act. It just sort of reinforces to me, though, that watercolors are far more forgiving than a lot of people seem to think they are.
So... There. .. Now you know.
"Truth is like the sun. You can shut it out for a time, but it ain't goin' away." (--Elvis Presley)