There's a reason why beauty writers talk about how to transition your skincare behaviours at this time every single year: not enough people are pro-active about the change. Too many ladies and gents only look for the winter-to-spring wisdom after their first major breakout or when a friend tells them their foundation looks chalky, but the logic behind transitional changes is that they need to be introduced into your regimen early enough that your skin can adapt to the changes in both environment and products. If it's when August when you suddenly remember, "man, I haven't worn SPF in three months," reach for some sunscreen stat and make a mental note to start much earlier with your summer-to-winter transition next year.