I've left the house warm enough to deal with the weather, and paid someone to patrol daily and check it weekly, including exercising plumbing and arranging for repairs. This for two years abscence.
My brother has been snowbirding stick and bricks for more than ten years, keeps the houses at each end climate controlled, an attended. He has had flood damage in the basement to deal with. At the northern end, our sisters and their kids watch and use his house, and one nephew house sat for about 3-4 years. A house sitter with proper authority and good communication can take care of just about anything. College students often work out if your season away is as long as the school year.
I have three Michigan snowbird cousins, none winterize when going to Florida, and again, there is someone attending to the house.
There is a risk. At another house left warm, and unattended while I was away for two weeks, an ice storm took out power lines, a hard freeze followed, and house got flooded from burst pipes running through the attic.
So if you don't have someone attending to the house, it is better to winterize it. Even so, don't let it go cold, deep freeze is not so good for a lot of what you leave in the house. Thus snowbirding will not always help you save on winter heating costs.
