The Three color three brush advice

I'm watching a series of vids on how to be a better painter and it starts with a basic premise. Most beginning artists put 15 colors on their pallettes and an array of brushes in range to be used. The first advice in the first vid says you'll never learn to mix colors unless you limit what you start with and learn to mix the colors. Then if you limit your brushes to three (I do only one) you force yourself to develop the way you paint rather than a zillion brushes. I think this line of thinking relates well to jazz or any way you improvise. If you can do two or things real well with subtle changes that makes for a better solo than 35 techniques you learned last week out of a book. This idea of simplfying to also work on the "mixing" of jazz makes sense also. So you might practice many many ways of going from one chord scale or pattern to the next rather than 10 different ways to approach a chord for variety.
It just struck me how easy it is to get lost in the choices. K