When I lived in the UK, my horses both owned to turn out blankets, and a stable blanket, and some extras just in case. They were blanketed a lot during the winter when it was cold wet and miserable.
My first couple of years owning horses in Canada here I didn't own a blanket, but now I have one turn out for Ace, and a selection that would work for the others if needed. Fortunately although we get temps down to the -40's mostly it is a sunny dry cold and the horses are perfectly happy in it. There will be a few days here in fall and more in the spring that I have to watch carefully to make sure that everyone is doing OK.
Mind you I own a bunch of easy keepers, they go into winter fat and sassy and usually come out of it the same way