The longest I've gone without a shower was a few days when ill. Normally, I shower 1 or 2 times a day, always in the evening, also in the morning if I leave the house. I showered 3 times when I went to sports trainings, third time before the training.
I get told I stink if I don't take a shower just before leaving the house, I sweat a lot and have greasy skin. I have been using Gilette antiperspirant deodorant in a stick for some time now, it works to use it on the back and chest too, it doesn't stick, itch or leave stains.
I change underwear and shirt everyday. Other clothes when they get dirty or seem not fresh or smell sweaty. Laundry - as needed, not everyday for sure, sometimes I don't do laundry for two weeks and then do it a few times. Sometimes I'll do some every few days.