Still, you should wash your hands at least once a day. Whether you think you need to or not.
Absolutely right, I believe! Last time I had one of these kind of bugs was in 1979, and I've experienced no stomach and/or intestinal problems of any type since then. I'm by no means a "clean freak", have never used an antibacterial soap, don't obsess about public bathroom conditions or touching commonly used items or surfaces, and I work in an environment where people come to work sick a lot (because we're not paid if someone else must substitute for us) and we are frequently in much closer proximity with our co-workers than the distance between typical office desks or cubicles.
The household I grew up in was one where everyone (myself at the time being no exception) would get at least two incidents of either cold, flu or "stomach bug" annually, and for everyone remaining in my family, from what they tell me, this is still pretty much the norm. Only differences between their lives and mine currently seem to be our diets and our responses to minor illnesses/injuries/discomforts when they do occur. They're all big meat eaters, and I, while not a vegetarian, eat fresh fruits and vegetables daily, but have meat only once in ten days or so. Also, for the most part, they're the sort of folks who will go for a pill to alleviate anything from a headache to a sprained toe, and I never use pharmaceutical medicines, not even the over-the-counter ones most typically taken for granted. I find that a cold, for example, on the rare occasion when I get one, lasts a much shorter time without "help" from drugs.
I think there's a lot to be said for keeping one's immune system strong. Mine seems to be stronger than most people's.