Dad’s short answer: Three minutes after every single job: empty and rinse the dirty tank, flush clean water through the hose and tools, clear the brush, and leave everything to air dry. That's the entire routine, and it's not optional.

After every job

Empty the dirty tank and rinse it properly. Not just tip it out — rinse it. This is the one people skip and it's the one that causes the smell.

Run clean warm water through the machine and the hose to flush residue out of the lines.

Pull the brush roll or brush head and clear the hair. Wet hair left wrapped on a brush is how brushes go bad and how a machine starts to smell.

Rinse the hand tools and any small filter on a pet tool.

Leave everything open to air dry before it goes back in the closet. Caps off, tanks separated.

Periodically, and what wears out

Check the brush for worn or splayed bristles. A worn brush doesn't agitate, and that shows up as the machine seeming to clean worse.

Check seals and gaskets on the tanks. A perished gasket means the machine loses suction and you'll chase it as a motor problem.

Descale if your water is hard and the machine has a heater, following the manual.

And run the parts check before you buy any machine — brushes, tanks, gaskets, hoses. Same rule I apply in every category on this site. A carpet cleaner you can't get a brush for has a short life, and these are machines that should last a decade with this routine.

Dad’s Take: Three minutes after every job. Rinse the tank, flush the hose, clear the brush, let it dry. That's it, and it's the whole game.