Black lingerie suits anyone who wants one drawer that just works without thinking about it, the bra and knickers you reach for on a Tuesday with no occasion attached. It's less kind to anyone who only ever buys black because they've been told it's the safe, slimming option, because on a lot of bodies a good nude or a rich berry does more for the skin than black ever will. If every single thing in your drawer is black because you've never been shown anything else, that's worth questioning, not because black's wrong but because it shouldn't be the only answer by default.
The difference between a bra that earns its spot and one that ends up at the back of the drawer within a month is almost always in the build, not the colour. Cheap black lace goes a strange grey brown after a few washes because the dye wasn't set properly, and you notice it fastest under certain tops where the fabric's thinner. A decent one keeps its actual black, and the underwire stays put instead of migrating towards your armpit by lunchtime. Check where the cups meet the band, because on a lot of high street plus ranges that's where corners get cut, the band's graded up but the cup's just stretched wider rather than reshaped, so the fit sits wrong on a fuller bust specifically. Hand wash or a mesh bag on a cool cycle keeps the elastic honest for longer than the label usually promises, and a bra thrown loose into a washing machine drum will twist its wires within a season, I've lost more than one that way. Hardware matters too, a flimsy hook and eye set will warp first, so check it closes smoothly rather than fighting you, and look at the strap adjusters, plastic ones crack with wear in a way metal doesn't.
Black lingerie clashes with white or very pale thin fabrics for obvious reasons, but it also fights with anything sheer and loosely woven, where the seams and lace edges print straight through in daylight in a way they never do under a shop's lighting. It's the wrong choice under anything you need to feel barely there, a slip dress in a light colour wants nude or skin tone underneath, not black doing its own silhouette on top of yours.
Look at the cup seam first, run a finger along where it meets the band, if it's flat and sits smooth that's a good sign the fit was actually considered rather than just scaled up.