There are “go-to” things in life that give everything you need, and a flannel suit is my perfect cold-weather fabric. Flannel is simply wool brushed to create extra softness. The warmth of the cloth will depend on the napped surface. So the more nap, the happier you will be. I usually wear it grey and the very fine pinstripes add a little extra. Tailoring must be extremely fit in my opinion, but that’s up to you and how comfortable you want to feel.