I'm doing something similar -- taking a sabbatical to focus on learning and doing projects I didn't have time to do while working -- but I treat it like a job:

I'm doing something similar -- taking a sabbatical to focus on learning and doing projects I didn't have time to do while working -- but I treat it like a job: I read/write/code roughly 8h a day, 5 days a week. Just like in a real job there are some days I'm more productive than others, but I carry on. I still leave time off for family, friends and other persuits; on weekends and holidays I don't do as much reading, or none at all. I know if I'd do it every day I'd eventually burn out or allienate people around me. I can get pretty caught up in something when I'm interested in it and forget the world around me. So I'd just say daily consistency is not necessarily everything, it's not like a physical activity. You have to think a bit longer term and ask: do I know more today than a month ago? Am I still enjoying it?