IT’S NATURAL to worry about germs and bacteria, especially as we age and our immune systems can become weakened. But “your home isn’t a petri dish growing scary diseases at every turn,” says microbiologist Shaun Veran. And some exposure to microbes, Veran says, is like a “workout for your immune system, teaching it to recognize and fight diseases more effectively.”

Gastroenterologist Robynne Chutkan, author of The Microbiome Solution and host of the Gutbliss podcast, says a good rule of thumb is to clean your kitchen nightly and the rest of the house weekly. More frequent cleaning is needed only for visible dirt, grime or mold or when someone in your household is ill.

Introduce good microbes into your home, says microbial ecologist Jack Gilbert of the University of California San Diego.

✦ Open windows.
✦ Let pets romp indoors.
✦ Grow potted plants.

Studies show that these three things lead to a higher level of beneficial microbial diversity inside the home, Gilbert says. —Matt Alderton