I have a pair of the mountain horse rimfrost winter boots that I've had for 9 years now although for the past few years I've been eyeing a pair of insulated ariat field boots(used to sell the Bromonts at the local tack store). At a previous barn we used to hack all winter in the snow and only wouldn't go if it was below -15C with the windchill. I used to layer up my breeches and wear a pair of wool socks with my winter riding boots. I had peacock stirrups (the ones with the rubber bands) for hacking so I never had any worries about the width of the boots. But I find they're quite stiff for schooling in and use my field boots for as long as possible in the ring. Even with warm socks I usually end up having to use the winter boots if it gets below 0C.