The corners where two walls meet the ceiling are some of the least disturbed spots in any home. Nobody walks past them, nothing brushes against them, and air barely moves there compared with the rest of the room, which makes them the perfect place for a cobweb to form undisturbed for weeks at a time.
A single thread often goes unnoticed until it catches a beam of light from a window or lamp, at which point it suddenly seems far more obvious than before. By then, several threads may have joined together, sometimes trapping a fine layer of dust that makes the whole corner look greyer than the rest of the ceiling.
A quick check with a long-handled tool
A soft brush attached to a long handle, or a vacuum cleaner with a narrow nozzle, reaches most ceiling corners without needing a ladder in an ordinary room. Working slowly around each corner, rather than sweeping quickly, helps catch the whole web instead of leaving loose threads floating down afterwards.
Light fittings and the tops of curtain rails are worth checking at the same time, since cobwebs often stretch from the ceiling corner across to the nearest fixture. Taking a moment to look up properly, rather than glancing briefly, usually reveals more than expected in rooms that are not checked often.
It helps to build this into a seasonal routine rather than waiting until a cobweb becomes obvious from across the room. A short walk around each room with a duster on a pole, done every couple of months, keeps the ceiling looking consistently tidy without ever becoming a big job.
Corners above wardrobes, behind doors, and near the top of staircases tend to collect cobwebs fastest, simply because they are checked even less often than the rest of the ceiling. Giving these spots a little extra attention makes the whole home feel properly cared for, right up to the highest corners.