almost always wear shoes in an apartment

of course there are always exceptions. apartments are lived in by a passing parade of humanity, many of whom you are fortunate to never meet. there are sweet young things and probably serial killers. they move from place to place, and if you are doing the same, you walk the same filthy shag carpets they do. you can use dry carpet powders and even wet carpet cleaners, but there is no real solution. the best i did in one house was to pull up all the carpet and pour several GALLONS of white vinegar on all the bare wood floors, let that soak in and dry over a few days. then put in new carpet. this is impractical in most apartment situations.

besides the biological hazards there are the physical dangers. There have been stickers and even an open safety pin in the carpets. thankfully a tennis shoe caught the needle of the safety pin. just keep those shoes on.