Here in Brazil it's very common to have several showers a day. I, for example, take two. The first is when I wake up, before I go to work, and the second is when I get home from work. I wake up at 6.30am and get home at 8pm.
Kinda but it's much less of a concern for me as all surfaces can be cleaned but with hot tubs they often have pipes that cycle the water that never get a scrub.
Interesting. Swimming pools also have pipes that cycle water. And ideally you are keeping the water maintained and doing regular deep cleans of the tub anyways
It's not binary of has pipes or not and cycles water or not. It's the amount of it as well as the use of hot water. I don't know if this is just personal experience but hot water is a much better solvent than cold water and a pool has a lot more water while a hot tub has quite a minuscule amount of water that is circulated quite quickly.
Really it's not that big of a deal and I'm not saying it's unhealthy but just how I find them to be disgusting.