I’ve lived on a boat for the last eight years, seven of those being completely ‘off grid’ so am used to being frugal with everything. Most of our leccy is 12v and comes from our battery bank. Our gas is in big, metal bottles. Hot water was made when we ran the engine. As we had to carry our domestic water with us and find a water point to fill our tank, we made a tankful last a fortnight. We have ‘boaters showers’ - get in the shower, get wet, turn off the water, soap up, turn on the water and rinse off. Washing up gets done once a day, saving both water and washing up liquid. Our journeys were planned to include supermarket stops. The hardest part was making the rum last long enough before the next Aldi (other supermarkets were available, sometimes).
Now we’re in a marina with leccy hook up and a tap for us to fill the tank, we are still careful with what we use, especially the LPG as we find the bottles get heavier and, therefore, harder to change as we’ve got older. Our hot water now comes courtesy of an immersion heater and, with red diesel prices now as high as white diesel, works out cheaper than running the engine. Our battery bank is topped up with an electric battery charger, again, cheaper than running the engine.