A lot of flies, mosquitoes and other crawlers come into the apartment. It helps against many types of insects to set up traps and catch them.
For example, you can put sweet food leftovers in a bag and leave them for a while. Fruit flies and other interested parties then crawl into the bag, which you then just have to close and throw away. You can diffuse essential oils around the home or spike a lemon with cloves and place them in the room. Mosquitoes in the apartment can also be quickly driven away with certain smells. The coffee trick is said to be particularly helpful against wasps: coffee grounds are dried and placed in a small bowl. The smell of the smoldering coffee is supposed to keep the winged nuisances away. If there are holes in clothing or sticky threads in food, this indicates a moth infestation. If you have a lot of crawlers in your apartment, you should look for such cracks and seal them as airtight as possible.