Look, I get it, some people like the palette they work with. That's completely acceptable and I certainly have colors that I like more than others as well. But the answer, as always, is that it depends. Really, it depends. If you want to paint earth tones then break out your earth tones. If you want to do all blue then leave the yellows in the drawer. Deciding what you're going to paint, if even you're not sure how you'll get there procedurally, can be a pretty big deal at the outset.
I think about every single painting before I begin work. Sometimes that thinking takes five minutes. Sometimes it takes years, but I always think first and then get to work once I finally know what I'm doing. My process is more emotional in that I need to feel it to visualize it, but when I do I approach my painting with the right palette in a much more confident and declarative manner.