The vacuum that lost its suction: filter, hose, brush - ten minutes, three suspects

A vacuum that will not pick up is almost never a dead motor - the suction dies slowly through three ordinary blockages, each with its own audible tell, and the whole repair is a screwdriver at most and a bin bag of dust at worst. Work them in order and you will finish before the kettle does.

The three suspects, in order of how they fail

• The filter - and the sneeze test: a clogged filter turns the motor's note from a roar to a whine and the exhaust into a dust cloud; that sneeze at switch-off is the machine telling you its felt is done. Pop it out, hold it to a window: grey through the whole body is a clean-now, dust with clear patches is a tap-it-out-over-the-bin. Foam and felt filters take a rinse and a 24-hour full dry - a damp filter is how a healthy vacuum smells like a wet dog for a month and how a motor's bearings meet corrosion - so the desk's rule: wash on the morning of a day you'll park the vacuum open anyway, never the night before a clean.
• The hose - the coin trick: the blockage lives where the wand joins the hose or at the handle's bend, and its signature is the change in pitch when you uncouple: suction strong at the body port but nothing at the wand means the throat is shut. Detach, look through against a window, and for the stubborn half-block a long flexible brush down it - or the old method: one end into a running tap with the other up over the bin, and let the water push what the dust won't release. Reattach with a half-turn of each fitting's collar; a loose hose coupling sucks air and reads as dead suction.
• The brush roll - the haircut: on uprights, a roller wound with hair stops spinning and the machine polishes the carpet instead of combing it; the sound is a rattle before it goes silent. Two coins or a flathead at the soleplate's tabs, the roller lifts out, scissors along the moulding line at each end - cut the wound, never slice across the bristles - and the roller returns with a quarter-turn of the bearings' seats wiped clean. The same thirty seconds reveals the soleplate's inlet behind it, where a sock or a spoon from under the fridge usually finishes the story.

When it is the motor, by elimination

Clean filters, clear throat, free roller, and the suction is still weak: check the bag or cyclone's seal - a bin not clicked home or a bag's cardboard collar knocked off makes the whole system suck around the mess instead of through it - then the belt (on driven heads the roller spins via a rubber belt; stretched, it slips and screams faintly under load). After that list, a whine that doesn't change with anything is a motor's fan worn smooth, and the repair quote against the shelf price is the honest arithmetic the buying guides already walked through; the good news is that on uprights the fan failure rarely explains the slow-death suction pattern this page opened with - those three blockages explain it most weeks of the year, for free.