No matter how careful you are, and how many times you wash your hands, you can't avoid germs entirely — but you might not be doing all you can to keep your family healthy. Step up your sickness prevention plan with these tips. 1. Open your windows Recycling inside air does wonders for temperature control, but it can turn into a hotbed of sickness if you’re not careful. Infectious germs multiply quickly, and in a closed system, the bad germs can take over.