Yes it is okay.
Worthwhile if you don't use it for a year but not worthwhile if you go there every month. Turn off the water heater heat and drain the tank and leave the drain valve and also several hot faucets open.
(Be sure to refill the tank to the point of having a hot water faucet open and running smoothly before turning the water heater heat back on.)
The disadvantages of crab apple trees. In summer, the apples are too sour to pick and eat. In winter the birds come and leave dropping all over the place.