Any harm in rinsing watch daily?

I rinse pretty much every day since my Fenix 5 - 5+ and now 6ST

I have not seen any problem. I dry it off afterwards and blow the water out the charging port, shake it a bit and that's it.

I previously had a fenix 5+. I wore it continuously...in the shower...in the lake...in the ocean...in the rain. I never gave any thought to drying the watch or worrying about the ports for the pressure sensor. I figured wearing it in the shower was enough to deal with any sweat accumulation. In over a year's time, I never experienced any issues with the pressure sensor, the bands, the buttons, the charging port, or anything else. Now I have the fenix 6x and am treating it the same way. Although I don't think there's any harm in trying to take good care of the watch, I believe the fenix watches are built for rugged use and wear. The only time I take it off is to charge it. That makes for an awesome tan line!!

Exactly!  Never comes off.   In fact a good rinsing a day in the pool is good for the sensors

I don't

meaning i take it off and wipe it with a towel when i am out the shoiwer.

I dont do any sximming activity neither so no exposition to water elements.

On a related point, do people wear their watch in hot tubs?

I have worn it in the hot tub. The watch is rated for normal use in temperatures up to 45C / 113F.

Garmin's official recommendation is to rinse the watch with cold water after every activity.

I interpret that to mean it's probably fine to also rinse it daily even if you didn't do an "activity" that day. It's designed for swimming after all, so I don't see how a little tap water for a few seconds a day is going to hurt anything. Just make sure you don't use any soap that could clog the barometer - bar soap, for example, is a bad idea. However, an occasional rinse with some liquid dish soap diluted in water is probably not a bad idea.

Hot water is a bad idea - it causes the watch body (and internal gaskets) to expand and contract, which could compromise their water-tightness.

jlgranth said:

I have worn it in the hot tub. The watch is rated for normal use in temperatures up to 45C / 113F.

The temperature rating does not take into account being submerged in water at those temperatures. I'd recommend against keeping the watch submerged in hot water, see my post above this. To each their own, if it's a risk you're willing to take with your watch, that's ok. And honestly it's probably fine. But for myself, I'd rather not risk weakening the integrity of the waterproofing just because I'm too lazy to take it off in the hot tub. It's not like I need to be wearing it while I'm in there, it's a hot tub - I'm just sitting there doing nothing. Sounds like the perfect time to put the watch on the charger.

Also, hot tub water is gross, it's full of skin oils. All that foam that accumulates on the surface when the jets are on? Skin oil. Yuck. Rather keep that water out of my barometer ports if I can.

Absolutely none at all. I shower with mine at least once a day. It gets sweaty, pool chlorinated water, sea water, and showered. Just like all my Garmin watches before. The best it will get afterwards is a wipe down with a towel. And still it keeps going without any fuss or bother

Rinsing it daily shouldn't cause any harm.  That being said, I shower with mine, but make it a point to rinse it again in the kitchen sink afterwards.  I have a lot of minerals in my water.  I can see calcium and lime build ups on my shower head after a couple of weeks if it isn't cleaned regularly.  My kitchen sink has a water purifier attached.  I read a while back of a 935 user having problems with his barometer.  He used a Water Pik to clean the port. (not recommended).  Anyway, he said he had lime deposits in the port holes, so I do my "routine" just to be on the safe side.