I work on the basis that, if i was coming out of a centrally heated house, (and mine do, they all live in) i'd feel the cold, so i put a coat on, when i reach the place i want to run the dogs, the dogs get a ten minute run around, then the coats come off, because by then their normally panting and don't need them anymore, shit side of it is, i get to carry the buggers for the rest of the mooch mags the deerhound x doesn't wear one, unless it's road work on a very cold & wet day.
I've never had a dog cramp up yet, so if it works for you and your dogs carry on. but i'd like to