I used to divide my outfits into two camps: goes with black and goes with brown. Because black and brown were the only neutrals I used. That doesn’t really work any more, at least not for me. Turns out that while a lot of things will work with black or brown, some things don’t.
So now when I buy accessories (particularly shoes) and I’m trying to fill gaps in my wardrobe, I don’t think about black vs. brown. I think about warm vs. cool. So warm tones are reds, yellows, and oranges. Cool tones are blues, purples, and greens. And you have cool neutrals (blacks, greys, bright whites) and warm neutrals (browns, creams, beiges). If I realize that I really like wearing boots, my goal is (over time) to always have at least one cool pair and one warm pair.
Right now I have 3 pairs of tall boots that I really like. Black, grey, and cream (grey and cream pictured above), and so no matter what colors I’m wearing, one of those will work with it. I’ve done the same things with heels my heels and flats.
This is also a great way to pack your suitcase for travel. Try using only cool tones or only warm tones, so that you can more easily mix and match your outfits.
I’m not suggesting that you immediately shop to fill your closet with duplicates of shoes or purses in both warm and cool tones. But if you’re trying to build or maintain your wardrobe effectively or create a capsule wardrobe for travel, try thinking of warm vs. cool.