Short answer: a monthly maintenance wash, the seal wiped weekly, and the filter cleared every one to three months.
If your washing became clean but the machine smells, this is why.
The schedule
| Part | Frequency |
|---|---|
| Door seal wiped dry | Weekly |
| Detergent drawer rinsed | Monthly |
| Maintenance wash, empty and hot | Monthly |
| Drain pump filter | Every 1–3 months |
| Behind and under the machine | Quarterly |
| Inlet hose filters | Annually |
Why they smell
Two causes, and both are about residue rather than dirt.
Too much detergent. Almost everyone uses more than the dose, and modern machines use less water than the doses were written for. Excess detergent does not rinse away, it builds a film in the drum and hoses, and that film feeds bacteria. If your machine smells, halve your detergent before you do anything else.
Cold washing. Washing at 30°C is good for energy and fabric and bad for the machine, because nothing ever gets hot enough to break down that film. A monthly hot cycle is what compensates.
The monthly maintenance wash
Empty machine, hottest cycle it has, with either a proprietary machine cleaner or roughly 250ml of white vinegar in the drum. Do not add detergent. You are removing residue, not adding more.
While it runs, wipe the door seal. On front loaders, fold back the rubber lip and clean inside the fold. That fold is where black mould appears, and it is the single most common source of the smell.
The filter people never find
Front loaders have a drain pump filter, usually behind a small hatch at the bottom front. Most owners do not know it exists until the machine stops draining.
Put a shallow tray and a towel down first. There will be more water than you expect. Unscrew it, clear it, rinse it, screw it back firmly. Every one to three months.
The habit that prevents all of it
Leave the door and the detergent drawer open between washes. A sealed damp drum is an ideal environment for mould; a dry one is not.
Also: take washing out promptly. Leaving a wet load overnight will make both the clothes and the machine smell, and re-washing costs more than remembering.
Dryers
Clean the lint filter after every single load. This is a fire-safety issue, not a maintenance one, and it also cuts drying time noticeably. Vented dryers need the duct checked annually.
If you would rather not think about any of this, laundry appliance interiors are part of deep clean scope rather than a regular clean.