Hair color choices and undertones

I'm reducing my wardrobe and would like a small group of colors that works with the clothes I already wear. I keep finding similar tops that work differently with the same jacket. I don't need a perfect seasonal label, but I would like to understand why some combinations look calmer than others. I'm considering a couple of base colors plus one accent. Before removing anything, I want to try each top near my face in the same daylight and take notes. I'd also compare the colors with the jacket I wear most often. I found a guide on find my color palette while looking for a sensible way to organize that test. Is it better to settle on an accent only after testing the basics? I want to avoid keeping colors just because a chart says they belong to my season. What number of core colors felt manageable for you? I can lay the candidates out together before deciding. That should show which combinations I actually wear. I'm interested in a process that helps me use what I own before buying anything new. A practical order for comparing pieces would be appreciated.