1. When to do a lesson
There is no prescribed time. Get on the floor at any time, and your state will shift just by engaging with the movements. Sometimes it's useful to do a lesson in the evening when you're tired because it down-regulates the system and elicits the parasympathetic phase. Or, it might feel right to do a lesson in the morning when you can pay attention. I feel energized if I do a good spine lesson in the morning.
2. Should you repeat a lesson?
There are no shoulds. You can repeat a lesson as long as it's interesting, but not as a mechanical exercise or to seek perfection. Notice how it affects you. Maybe it resonates for you in a particular way. Maybe you feel wonderful doing it. The more variable and novel input you can give your nervous system, the better you'll feel.
One option is to do a lesson a few times with your attention on different aspects of the movement. Sometimes I do a lesson five times, on different days, to explore how it moves through me. Other times, I wait a week in between to see if my experience has changed. Do what works for you.
3. How many reps?
Not that many. A few slow movements with deep awareness is better than many movements with mindless repetition.
4. How many lessons per day?
One, maybe two. If they're short, perhaps three. These lessons can be tiring because your attention gets tired. Notice how you feel and calibrate to that. Sometimes I'll do half a lesson, walk the dog, make a phone call, have some coffee, and then come back to it. At other times I'll do two lessons back-to-back.
The Treasury is designed for you to do one lesson a day for seven days, yet this may not be your rhythm. What is your rhythm?