There is an element of guitar playing which is very similar to athletics or sports activities. The use of our body to produce music means that we have to perfect the movements, just as a tennis player perfects his back-hand.
This is a time to review, confirm and perfect all the basic movements you need for a good technique. It should not be a time for learning new movements or extra difficult techniques. I see it more as if I were a beginner and I make sure that each technical lesson is properly assimilated. This confirms all the movements I will need for my music and makes my fingers more reliable under pressure.
Sometimes I feel it is better not to talk about it but simply to do it and each of us can discover our own routine that best prepares us for a day of practice.
A pupil drew this cartoon, while I was directing a warm up session during a course in Spain. It's great fun to do simple exercises (as a group or alone) and get into the habit of starting the day with a good warm-up routine.
Good luck and good practice, David.