Kia Ora,

Only when it 'rains' ...Besides, only 'dirty' people need to wash

Jokes aside...Once a day in the morning...Or occasionally if its been a humid day I might have a 'mandy' ie used in most hot Asian countries, a wash down use a bucket of water, very economical on water use but does the job...
I live on an island when most properties rely on rain water to fill their water tanks, and this summer has been the driest in thirty years, we haven't seen any rain worth writing home about in months...So water is scarce, we have to ration our supply...However there are bore water companies on the island who sell tanker loads, they're flat out and book up at lease a month...So in a sense the joke part could be serious, if we don't get rain soon...
BTW, too much washing/showering removes protective oils from the skin, so it pays not to shower too much and when you do you should use 'natural' soaps...
Metta Zenda :