I’ve changed everything since I met Greg’s method. Not just my warm up routine. I start my warm up every day with: stillness, energize the lungs, humming and release. I practice these 4 stages for a few minutes each. I continue with the first 4 stages of the singing c- series. I want to be very careful about the aperture corners. And I try to play all exercises passively. I keep humming and playing the low C. Then I take a break of a few minutes. Then I play some chromatic scales. Both slurred and tongued. A short break follows. I either continue with technical studies or whatever is pending.
That is my way to warm up. It feels good. The lips are warm but not stressed.