I do use the seasonal colors, but they are a starting point, not a finish line. And I don't care for the newfangled breakdowns - I think we should do our own.
Best Colors: These are the colors, when you wear them, people tell you how amazing you look. Time after time, these get you positive attention, from everyone from little kids to the lady in the back of the church.
Okay but not great colors: These colors work for you, but not all that well. I have strong coloring, so although peach and aqua are "my colors", coral and turquoise are much better. Quiet, every day, doesn't clash. Maybe a little too strong, maybe a little too weak, but - you wouldn't throw it out of the closet.
Colors that actively make you look ill: Everyone has that color, if you wear it, you will hear, "you look tired". You might feel the best you ever have. People will try to send you home for a nap.
Colors that wear you: These are colors that, on paper, should look good on you - but they don't. One of the reasons I like the seasonal colors is that the other types of color analysis forever want to put me in colors that wear me - like cobalt blue. It's not that these colors look *bad* on you, it's that people see the color before they see the you. These colors are also known as "that shirt looks great if I wear the right shade of lipstick".
Too bright/too muted colors: They are semi-okay, but somehow they make you look a bit hectic (if you wear muted colors) or a bit muddy (if you wear clear colors). Autumns, even redheads, don't generally look good in orange sherbert. You'd think they would, but they don't. I don't look good in teal. I can wear most other colors of blue-green, but teal is just ever-so-slightly off. (And not Chinese blue, which wears me).
The universe being limited, one wants to get as many as possible of one's clothes from the "great colors" bin, then get the secondary colors from the "okay" bin, eliminate the ones that make you look ill, and limit the rest severely. People are forever wanting to wear black and/or white - but those tend to wear the people, not the other way around.
There was a decade (we know it as the 90s) where they packed up all the color and took it away. Not great times for Springs. I wore a lot of charcoal, a lot of teal, a lot of oatmeal. All of those colors are marginal colors on me... but it was as close as I could come with what was offered. Let's be real - not everyone is going to sew, and even so, you're going to be able to get your hands on what you can get your hands on. I did what I could, and I accessorized brightly. But it was good to know where I was aiming!
Hope this helps a bit.