I was reading on the couch one evening, the kind of gray afternoon light that just gives up around five, and I had one overhead fixture doing a job it was never built for. Everything felt flat and a little institutional, like a waiting room. I pulled an old desk lamp over, angled the head down at the page, and the whole corner of the room changed temperature. That's the moment adjustable lighting stopped being a thing I'd put off buying and became the thing I actually needed.
If you own none of these yet, start with one good floor lamp that has a head you can tilt and a neck you can bend, rather than buying a pile of small clip lights. One flexible lamp solves more problems than three fixed ones, because you can point it at a book, bounce it off a ceiling for general light, or aim it at a wall for something softer in the evening. Get one with a few brightness settings if you can, since a reading light at ten at night should not be the same light you need for finding your keys at seven in the morning.
In an ordinary room, these sit well with other low, warm light sources, a table lamp with a fabric shade, maybe a string of something dim in a corner, so the adjustable one isn't fighting to be the only personality in the room. They're especially good next to a reading chair, a desk shoved into a corner of a bedroom, or a kitchen counter where you need focused light for twenty minutes and nothing for the rest of the night. Where they struggle is in a room that already has strong overhead lighting doing the heavy lifting, you end up with light fighting from two directions and everyone squinting. They also look a bit sad and clinical in a space that's trying to feel formal, a dining room with a chandelier doesn't need a gooseneck lamp with a visible hinge sitting on the sideboard.
I ignored mine for a year because I assumed "adjustable" meant ugly, all exposed joints and an industrial look I didn't want near my sofa. Turns out there are versions with a slim profile that disappear into a room until you need them, and that's the one worth hunting for, not the one that looks like it belongs in a garage.
Before you buy, measure the full reach of the arm extended, not just the base, because a lamp that looks compact folded up can suddenly need two feet of clearance once it's doing its job.