As I approach the 20th, I'm thinking I might just top out at 20 reps per day for the rest of the month. I'm starting to feel some strain in my knee ligaments when I do more than 6 reps at a time; and when my chronic pain condition acted up yesterday, I was not sure if the burpees were exacerbating it. I'm pleased that I've definitely gained some strength in the quads, though. May be best not to push it until I'm sure I'm conditioned to do 20 reps every day. Plus, between the holidays and travel and some medical procedures I have coming up in Dec, I think I won't stick to 30 per day during that month even if I am able to maintain it. I'll just aim for 20 per day the rest of Nov and Dec.