Neither rosemary nor sage like being pruned heavily. Sage is short-lived anyway, but pruning into the wood is asking for trouble. If you're going to mess with rosemary beyond light trimming, do it in the warm season when it is growing well. They both propagate easily from cuttings, though, so I keep a plant of each protected over winter and take cuttings in early spring. The new plants are more vigorous and give me better, more tender cuttings for cooking. My (protected) mother ARP rosemary is 15 years old, but I switch out the sage mother plant every year. BBQ rosemary is more tender than ARP, but I often find a few that survive the winter.
