4. Mold
Molds are a natural part of life, just as anything else organic to this planet is; however, there are a few kinds of mold you should be worried about. You shouldn’t have to worry about mold unless it enters your house through excess moisture either caused by water damage or other environmental factors. If you find mold in your home you should wash it off from all hard non-porous materials, and any material that is absorbent should be replaced. If the mold is extensive you may want to call a professional, just know that you can always buy at home test kits to see what you’re working with.