Professional extraction once a year removes the soil that has worked its way down into the pile. But carpet spends the other three hundred and sixty-four days under your care, and habits in that window matter more for the carpet's lifespan than the annual clean does.
Start with vacuuming frequency. Most people vacuum too rarely and move too fast. Traffic lanes deserve attention twice a week; the rest of a room once a week is usually enough. Speed matters as much as frequency — a slow pass lets the beater bar actually agitate and lift soil, while a fast pass mostly just moves the surface around.
The reason this matters is mechanical, not cosmetic. Soil trapped in carpet is abrasive. Every footstep grinds those particles against the fibers, cutting them a little at a time. Carpet in a heavily used room does not usually fail because it looks dirty; it fails because the fibers have been abraded until they lie flat and lose their texture permanently.
Spills need to be blotted, never rubbed. Rubbing pushes the spill deeper and distorts the fiber structure, which leaves a visible patch long after the stain itself is gone. Press a clean white cloth straight down, lift, repeat with a fresh section of cloth, and work from the outside of the spill inward so it does not spread.
Be cautious with retail spot removers. Many leave a sticky residue that attracts soil, which is why a treated spot often reappears darker than the surrounding carpet a few weeks later. If you use one, rinse the area with plain water afterward and blot it dry.
Entry mats are the cheapest carpet protection available. Most soil arrives on shoes, and a good mat inside and outside each exterior door intercepts a meaningful share of it before it reaches carpet at all. A no-shoes policy indoors does even more, though not every household wants to enforce it.
Do all of that, and annual extraction has far less work to do — and the carpet keeps its texture years longer than it otherwise would.