No matter how clean and tidy you are, you can’t help the fact that as a living being, you emit germs as part of your biological processes. It’s just what it means to be a human. In addition to the bacteria that you naturally produce, you also drag bacteria in from the outside. One study that examined what types of bacteria live on common household surfaces found that Staphylococcus aureus (Staph), yeast, mold, salmonella, escherichia coli, (E. coli) and fecal matter might all be living in your home. It’s no reflection of cleanliness habits – even those who live as if they’re in a plastic bubble will still find these germs in their homes. Think about it: you eat and groom yourself and sleep and drool in your home. You use the toilet. Germs are bound to happen.
Even if you run anti-bacterial wipes over every surface on a regular basis, there could be one thing you’re still overlooking. Or lots of things: the exposed items you use on a regular basis. Not everything gets stored comfortably in an airtight baggy or sealed container. You have a lot of things, from bars of soap to toothbrushes that are simply exposed to the air all day. While it can be a nuisance to remember to replace or clean these things regularly, it would be far more of a nuisance to treat an infection that came from not cycling them out.
Your skin contains a complex microbiome that’s made up of several types of bacteria. It’s good bacteria that’s meant to be there, but many of the things we use do alter it. That’s one reason dermatologists ask you to stick to gentle face wash since the harsh, chemical-loaded ones can mess up your microbiome. Really, anytime you interact with it, you disrupt it, and that applies to when you use a makeup sponge. You aren’t just putting makeup on your skin, but you’re also pulling bacteria off of your skin that then sits on the sponge. It might sit in a warm, humid environment like your bathroom where the bacteria can fester and grow. It’s a good idea to replace these every three months.