I drain our water heater at the end of our 2-4 month snowbird trip, this year 4 months. When were having our HW heater serviced the Tech. we had asked me if I drain it after returning home and I said yes we do. Since it is a Surburban HW heater I also change the rod in it weather it needs it or not. Last year we were only in this resort 2 months and the rod was about 35-40 percent gone. This year we are here 4 months and I had the water softener hooked up so I'm curious to see how much of it is left. The Tech said the worse thing you can do is leave the water in the HW heater from year to year hear, but this water is extremely hard.
I'm glad I dump it and flush, If I had an Atwood Heater it might make a difference but my Sunnybrook had one and I still drained it, as far as I know it's still going 12 years later.