I avoided bed frames for years. Mattress on a base, maybe a headboard leaned against the wall for show, and I told myself that was a choice rather than a failure to finish a job. What changed my mind was spending a weekend at a friend's place with an actual frame under me and realizing how much quieter and steadier a bed can be when it's built as one piece instead of a stack of other people's decisions.
A bed frame does not get on well with a room that's already busy underneath it. If you've got a patterned rug, heavy curtains, and a dresser with a lot going on, a frame with carved detail or an ornate headboard turns the whole room into noise. Dark wood frames especially need some quiet around them, or the eye never settles anywhere. The other place they struggle is low ceilings, where a tall headboard can make a room feel like it's closing in rather than anchoring it.
Where a frame sits well is in an otherwise plain room, which describes most bedrooms I've seen, rented or owned. Pair it with simple bedding, a couple of lamps instead of an overhead light, and let the frame be the one piece of furniture doing visible work. Solid wood frames, oak, walnut, ash, look right next to plain painted walls and almost nothing else, because the wood grain is already the texture in the room. Upholstered frames do the opposite job, they soften a room that's got a lot of hard surfaces, tile floors, metal lamps, that sort of thing.
Measuring is where people get it wrong more than any other part of this. You need the mattress size plus the frame's own dimensions, not just the mattress size, because a frame can add four to six inches on each side depending on the style. Measure the room with the mattress size you want already marked out on the floor with tape, then walk around it like you're getting out of bed at 2am to see if you clip a dresser corner. The other mistake is buying a frame too short for the mattress, so it rides forward and leaves a gap that catches socks and small children's toys forever.
What makes a good one worth living with, day to day, is something small: a center support rail that actually reaches the floor on its own leg, not just hanging off the side rails. I've slept on frames without one and felt every shift of weight all night. Find one with that and the rest of the shopping gets a lot less complicated.