Rarely on a site, where we could use their showers. So mostly use our shower cubicle. During warmer months, when we don’t have the boiler on we use a Hozelock portable shower with cold water topped up with a kettle (or two, if necessary) of hot water. This way we can both shower using only a total of 5ltrs of water thereby saving on water usage and emptying. Have been showering this way for years. In cooler weather we will use the normal inbuilt shower, again, being careful not to use too much water.