Clothes can come into contact with a variety of chemicals and pollutants from urban environments, cars, and workplaces. These can accumulate on bed linens, potentially causing skin irritations or other health issues. 

Outside clothes might harbor tiny pests like bed bugs, lice, or fleas. These hitchhikers can transfer to your bed, leading to infestations that are both costly and time-consuming to eliminate.

In conclusion, being mindful of not letting outside clothes come into contact with your bed is more than just a matter of cleanliness; it’s a matter of health. Fostering good habits in this regard can significantly enhance the quality of your sleep and overall wellbeing.