Now that I'm thinking of it, I have a lot of small habits that were once large habits. I can get up and go for a run any given day, and I might do it every day for months if I have time, or I may not. Doing 10 pushups a day is no problem even on off-gym days. I wonder how much of it is related to the fact that these stimuli are not novel, and I know I can do them effectively and don't have to slog through something where I won't see results. I'd still love to build up a reading habit again.