If I saw 50 cases in the three counties where I spend most of my time, I would absolutely self-quarantine. If I saw >500 identified cases in the US, especially if it happened rapidly (weeks) I'd be extremely cautious, but wait until the first cases started popping up locally, then quarantine.
What you are talking about is not quarantine, it’s precautions..
I currently do similar things during a flu outbreak..
I cancel any doctor or dentist appointments. I avoid closed or clouded public spaces..
When I got to a public place, like the grocery for example, I go armed with a anti-microbial, like alcohol.. I consciously avoid touching my eyes, or nose with my hands until I wash them. I also look for sick people..
It’s not hard to do..