I was thinking about how pianists practices scales. Scales are a practice for the most novice of beginners all the way through the most advanced of masters, but in some sense they are practicing different things. For beginners, scales are about fingering and evenness of rhythm. At my highest level of mastery (intermediate, let's call it), scales were about evenness of volume from finger to finger. I imagine masters work on scales to practice their tone.
Any daily practice will evolve as you improve in certain areas and find deficiencies in other areas. This is where I find myself now in my writing practice.