Three simple habits that have (anecdotally) cut down on colds for me:

* wear a mask in crowded environments where showing my face doesn't buy me anything (I don't wear one at work, but do at the grocery store or airport)

* wash hands before eating (or at least use hand sanitizer)

* grip the exit handle of the bathroom with a paper towel and dispose of it on exit

Not exactly double blind demonstrated but low cost and this year has been much better than last (which may also be due to my immune system having caught back up, too, so YMMV)

I do - it just makes sense if you are riding public transport or touching stuff that isn’t as clean as you’d think. Like your phone, wallet, keys, backpack, shoe laces, pant pockets, etc. Not obsessively, but if I haven’t washed my hands in a few hours or feel they are dirty I wash them before eating.

Spanish here. I do it all the time. I even carry a small bottle of alcohol in case I go to a place where I can't wash my hands first.

I would say most people do wash their hands here, however I have seen everything. From people not washing them to people using the toilet, not washing them, and then sitting on the table for lunch.

I'm Polish and I do - so do some of my friends. Typically right after ordering, before even the beverages have a chance to arrive.

My father would wash hands after petting a dog even, so I guess it's his germophobia that set the standard in my household.

I usually go wash my hands once I’ve ordered at a sit down restaurant.