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.
Twice. I am not a healthy human so I try and play on the cleaner side of life because getting sick is kinda easy and sucks a little extra like that.
Environmental guilt keeps them at seven minutes each average (yeah, I timed them. I don't even remember why, but that guilt seems viable enough)
Occasionally when the youtube hits just right the night time shower can be 15 minutes. Or it is complex grooming day and not just a shave or something.
I take as long and as hot of showers as I can because I know in 10-20 years, that will be a luxury. I also know that it's pointless for me to try to conserve. If me, all my neighbors, all my neighbors' neighbors, and everyone all of us knows made a pledge to use as little water as we could, it would be insignificant in the face of inefficient agriculture and corporate greed. Every one here could use over 50 gallons of water a day and it would still be absolutely miniscule compared to industrial use.
Anyone saying that water conservation should happen on an individual level is smoking some corporate BS. On an individual basis, there is enough water for everyone to live like a watery nymph if they choose to. It's corporations that are overwhelmingly sucking up the supply.
So take your time in the shower. Don't stress about frivolous uses right now. They won't be around forever and taking advantage of them presently won't do diddly to stop the future.
It's amazing, if you live in super rainy areas water isn't an issue. Probably never will be, at least in my lifetime. I only take 2-3 showers a week though. Showers irritate my skin.