I generally wore them continuously throughout the day. When I went to the bathroom for a urine break that’s when I would rewrap of course but I usually left the rings on and when I was done I’d just wrap and go. This took the least amount of time.
Early on when I was still conditioning and getting the wrap technique down I would take the rings off for an hour or so then reload.
As far as the taking them off for blood circulation, I usually didn’t have a problem with that. If I needed to take them off for a while it was usually because I wrapped to tight and my glans would swell up and ache, but within an hour or so I could reload and continue the day.
I don’t think its critical to keep them on ALL day long as much as it to wear them as much as possible. Sometimes its just not practical or perhaps your dick just needs a rest for the sake of the skin irritation.