Washing machines have filters to catch large debris; you should check these periodically and remove anything stuck in them. If you don't, it affects the machine's efficiency and eventually can lead to the filter getting clogged and flooding your laundry space.

Washing machines also need to be cleaned from time to time, generally by running them on hot with nothing in them except cleaning chemicals (you can buy washing machine cleaner, or google it for various diy solutions that probably involve vinegar or bleach). If you don't they'll start growing mold, and then all your stuff will come out of the wash smelling bad.

Dishwashers also generally have filters to catch large chunks of food and whatnot. Boy howdy can they smell bad if you don't ever check them.

There are dishwasher disinfectants as well, or you can do things with vinegar; either way, it'll prevent mold buildup and also hopefully rinse away buildup from soaps and whatnot.

If you have a reusable water bottle, wash it weekly. Otherwise you're probably drinking mold, the effects of which can be widely variable but almost always bad.

have a separate small garbage can for "wet" garbage such as food leftovers - they rot pretty fast so you might want to be able to take them out separately more often to avoid getting bad smells, mold and fruit flies

If you do get fruit flies, a small container of vinegar (like a small dip bowl) left on the table is a perfect fly trap

if you're not arachnophobic: don't kill spiders in your house, let them be - they are basically free labor when it comes to flies and mosquitoes

your shower curtain needs to be washed from time to time - it can get moldy if it's sitting in moisture, even if it's plastic. And that is no bueno for you

if you don't own an iron and for some reason need your clothes ironed in a pinch, hanging them in the bathroom while you shower will smooth out the wrinkles - the steam is both labor and work free!

wash your floors with hot (not boiling) water with cleaning agent - warm water helps soften any dirt quicker and also dries faster, which is awesome when you remembered your apartment is a mess 15 minutes before important guests arrive

"The world will know you as popstars. But you will be much more than that. You will be hunters."