A couple of interesting thoughts in habit-forming, from Andy Matuschak. I like the idea of increasing the amount of an activity in smooth increments rather than whole days:

When it’s time to ratchet up the target, adding one day per week to a habit can feel like a huge change! I find that fine-grained values work better when possible. For my piano practice, I don’t use “numbers of days practiced per week”: I use “number of minutes practiced per week.” I barely notice adding ten minutes per week to the goal, so I can smoothly ratchet up my target.

These fine-grained values also offer more flexibility. Say I want two hours a week of practice. That could be two big weekend practice sessions, or 15–20 minutes per day, or a 1-hour session with a couple smaller sessions. All those configurations hit my target, but the flexibility helps me maintain specific goals in the face of my shifting daily interest and availability.