A good pair of gold plated earrings catches the light without trying to. A poor pair sits dull and slightly orange under office lighting, and you can spot the difference from across a meeting room before anyone's said a word. One looks like gold. The other looks like it's apologising for not being gold.
Keep them away from anything else gold toned that's a different shade, because mismatched yellows next to each other on the same face look like an accident rather than a choice, not a style statement. The same goes for busy prints or anything with a lot going on at the neckline, a heavily patterned blouse will fight for attention and the earrings will lose. They also don't love being layered with silver unless you're deliberately doing the mixed metal thing properly, with a ring or bracelet to back it up, otherwise it reads as you couldn't decide. Where they genuinely let you down is anywhere that needs real durability, swimming, the gym, a job where you're constantly on the phone with your hand pressed to your ear. Plating wears thin at the point of most contact, and cheap plating can go patchy within a few wears, leaving a faint grey shadow where the brass or base metal shows through. If your skin tends to react to anything that isn't solid gold, check the listing for the base metal underneath the plating before you buy, because a reaction on your earlobe is not a subtle thing.
They're at their best for anything that needs a bit of warmth without being flashy, a daytime event, a dinner where you want to look finished rather than dressed up, the whole run from spring through to early autumn when your skin has some colour and gold sits against it properly. In the fitting room, or honestly just at your dressing table, do the obvious checks. Hold them up to a window and see if the colour looks consistent all the way round, not brighter at the edges. Run a fingernail lightly over the surface, if it catches or feels gritty rather than smooth, that's not a good sign for how it'll wear. Check the weight too, a stud that feels suspiciously light will often be the one that looks it by week three. If they're drop earrings, try shaking your head gently, if the fixing rattles rather than swings cleanly, that's a fit problem, not a style choice.
Tomorrow morning I'd put mine with a plain white shirt and nothing else on the neck at all, and let them do the one job properly.