After a couple of weeks off the horn for holidays (and trust me, at my level, it doesn't make much difference), yesterday and today I've played better than I have in years. Effortless, articulations good, intonation right on (OK, it's a wide-slotting horn, my intonation is always right on).
No hair on my lower lip. I shaved the beard off.
Could it be that simple? In high school, my senior year, my playing went to hell (still sat first chair of 15!). The hair on the lower lip started to grow then. I've had the mustache since I was 16 and only shaved it when my mother threatened to not pay for a senior/yearbook picture, and doesn't seem to make a difference but holy smokes, the lower lip fur-free seems to be a major improvement.
I guess if I ever grow the beard back I'll have to make sure that the lower lip stays clean!