Light-Up & Sparkle

LED light-up jumpers with the bulbs knitted in, plus sequin and glitter designs that catch the room’s light with no batteries to die at nine o’clock. Listings say whether the battery pack detaches for washing, because that is the thing everyone forgets to check.Before buying, read six things that go wrong with light-up jumpers — nearly all of it is avoidable with ten minutes of preparation — and how to wash one without ruining it.