If you look after your machine it will last longer. Give it a thorough clean, say, monthly/every other month, depending on use.
To get rid of powder buildup, stains and bacteria, put two cups of bleach in the powder tray and run an empty cycle on a hot wash. Then do the same using vinegar on a 40 degree wash to get rid of any odours.
Remove the powder draw and place in a sink of hot water and a cup of bleach and leave to soak for an hour or so.
Using the water from the sink and a clean cloth, thorough wipe around the door seal, making sure you get deep inside and remove any objects that might be there.
Using the water from the sink again, wipe inside where the soap draw goes and use a toothbrush to get into the nooks and crannies.
Wipe inside the washing machine and wipe the door.
Now wipe the outside of your washing machine, again using the water from the sink which has bleach in it.
Then use a clean dry cloth and wipe inside and out.
Now dry off the soap dispenser and put back in your machine.
It is important to leave the door open in between washes to keep it smelling fresh and clean.