As far as the housing part is concerned, check the functioning of the utilities and of the electrical system, for the fridge, the stove and the boiler it is necessary to clean the drains and the burner at least once a year to optimize operation, and remember that the fridge thermostat must be kept about halfway up, even in the middle of summer.
Also the drinking water and recovery tanks need a clean and a disinfected one to avoid bad smells deriving from the drains.
And don't forget the check coupon to check that there are no water infiltrations.
We are at your disposal for any advice or information.