I mostly go with what Snickers wants during winter. Sometimes he prefers slow walks, but sometimes he is full of energy and insists on fast gaits, even if I would have chosen something slower. But hey, if he feels fine to do it, why should I resist. He lives 24/7 outside, all the same, and can canter and gallop along the pastures as much as he wants - carrying me for a while during that doesn't change much, I suppose.
And I LOVE riding bareback in winter - Snickers is so warm and fuzzy, and helps me keep myself comfortable, if it is really chilly.
I have come a long way, to surrender my shadow to the shadow of my horse.