The quote above is a favorite of mine because it it applicable at every moment of the day. If you have read through the Stoic Week Handbook, you'll come across the term "stoic mindfulness." I believe mindfulness and the attention Hadot references are the same. As Stoics move through the day, we seek full engagement with the world. We work to be conscious of our choices and intentional in all our actions.
It takes energy to remain engaged in every moment, both mental and caloric. I had low blood sugar a few days ago and was on shaky auto-pilot until I found a snack! Volition (will-power) has to be built up and honed. We must practice our mindfulness.
The most important part of this week*, for me, is the reminder to be mindful. I want to be fully engaged with my life. There is immense value in morning and evening meditations, visualization techniques and the like, but the hard work of Stoicism is in whatever moment is before us.
*I say this entering the week, we'll see what jumps out at the end.