Here's the scene, and it's a repeat of a hundred patio evenings I've watched: the table is dressed, the string lights are warm, and the LED candles on every place setting are glowing exactly like the ones in the shop window. Then a glass gets knocked, someone laughs it off, and forty-five minutes later you walk around the table and half the flames have gone brown and dead. You told yourself these were outdoor candles. They weren't.

The problem is that most flameless candles sold as 'for indoor & outdoor use' are indoor products with a green leaf sticker on the box. The label is marketing, not a spec. Three numbers on the back of the packaging decide everything at hour five, and almost nobody checks them because the words are in a different language.

1. The IP rating is a range, not a yes-or-no

IP stands for Ingress Protection, and the two digits do two different jobs. The first one is dust — irrelevant to a candle. The second is water, and this is the one that matters. IP54 means protected against splashes from any direction, not against being doused. IP65 is the line people point to, but '6' only means a tight seal against a low-pressure jet for about three minutes. The moment a spilled drink pools on the tray, or a drizzle sits on the holder for twenty minutes, you are past what IP65 was ever promising. IP67 means one hour in a centimetre of standing water, and that is the grade I actually want for a table that will get food and drink on it. When in doubt, I ask the supplier for the test report, not the sticker. A candle that survives a splash test in a lab will still die on your patio if the seal is a rubber gasket that cracks in the sun — that crack is the real failure, not the IP number.

2. The battery hours are a marketing number

Every box says 30 hours, 40 hours, sometimes 100 hours. That figure is measured in a lab, at room temperature, with the flicker turned off, on a fresh cell. Your dinner is none of those conditions. Three things eat the runtime. First, the flicker mode — the one that makes it look real — draws noticeably more than steady-on, and it's the mode everyone runs. Second, cold. A cool evening in September is easily ten degrees below the lab, and lithium cells lose a chunk of their usable capacity as they drop; a candle that gives you nine warm hours in June will give you six in October and you will not have noticed why. Third, the driver. The cheap candle uses a regulator that sags under load, so the last third of the battery gets wasted blinking a dying flame instead of a clean one. The honest number to plan a garden dinner around is not the box figure — it is half of it. If the box says 40 hours, budget for a two-to-three hour evening with a spare cell in your pocket. I carry spares for a reason, and so should you.

3. The UV fade you can't see until the third party

This one is silent. The first two parties the candle looks perfect. Then the flame tip — the part that's usually a translucent white or amber plastic — starts to yellow, the clear base goes hazy, and the whole thing reads 'used' in a way a flame never would. It's ultraviolet light working on the plastic over weeks of afternoon sun, and it doesn't announce itself. If the candle lives on a south-facing table all summer, plan for the plastic to look tired by late August. The fix is boring and works: keep them under a small awning or under the string-light canopy, or buy ones with an opaque or tinted base that hides the fade. A candle that's been glowing beautifully on a shady side table all season will still look new at the end of it; the one out in direct sun won't.

The checklist I actually run before a seated outdoor event

Three questions, thirty seconds, done before the first guest arrives: Can it sit in a centimetre of water for an hour (IP67), or at least take a hard splash without weeping (IP65 at minimum)? Do I have enough charged cells to cover half the advertised runtime for the whole evening, plus one spare? Is the table in shade, or is the plastic going to look old by next month? Answer those three and the candles will be the last thing anyone on that patio ever thinks about — which, for a light, is exactly the point. If you want a set that already clears all three, our remote-control wax-look candle set is built for exactly this table, and the whole range lives under LED candles.

The rest of the table dressing is the easy part. Pair the candles with the string and icicle lights for the background glow — same warm-white logic, different altitude on the wall — and the room reads as lit, not decorated.