CarRentals did a study on people and their car cleaning habits, such as how often they vacuum and sanitize them. A whopping 32% of people clean their cars once a year, 12% reported not cleaning it at all, and 20% of people eat in their car. The study also reports 700 strains of bacteria can be living in a car at any given time with the hotbed areas being the steering wheel, gear shift, control knobs, seat belt, and door handles. Now granted, not all of those germs are harmful, but some such as MRSA can potentially threaten the health of someone whose immune system is weakened or compromised.