I personally don't feel a need to scale back at all in winter, I think a lot of us don't ride enough volume or race that much to leave one that trashed and needing a break. I've been keeping a 14-16hr training week, usually 14 these days as it's all indoors. Since November I've done the following blocks: 1) sweet spot 2) over-unders 3)vo2 4(current) mix threshold and vo2. These are made up of 2 interval training days and 4 endurance days. With easy weeks every 4 weeks, I'm always able to recover and am rarely burned out from volume/intensity