I tend to binge on fandoms--that several year stretch where it was all Supernatural, all the time was kind of unusual for me--usually these things come and go after a couple months. Star Wars and Middle Earth are the only other fandoms that can match it for staying power, but I never wrote anything for Middle Earth (and have never felt an interest in doing so, aside from maybe an essay on how the frequency of songs within Lord of the Rings tracks with how dire the situation becomes; Fellowship of the Ring is functionally a musical), and Star Wars infected me at such a young age that it's simply a part of my being. (Which may explain why it's the one franchise where I feel no compunction about picking and choosing what I'll treat as canon--the weirdness of some of the EU novels taught me the necessity of that in relatively short order.)
Writing and exercising function much the same way, though on a more week-to-week scale. Really, college was the only time in my life where I managed to balance most aspects of life for years instead of mere days/weeks. And that, I'm sure, happened only because I had an external and unyielding framework to fit myself into--everything was pretty much scheduled for me, I just had to show up on time and make sure to get enough sleep to continue doing it all.
Outside of that, posting to LiveJournal is probably the best I've done with maintaining a regularly occuring task, and I suspect it's because I've developed it into another (much smaller) external but slightly more yielding framework. There's the calendar down in the bottom right corner with its days that are either full or not; there's the loose posting schedule of Sunday = sacred music, Monday = poetry, Tuesday = review/random thinky thoughts, etc. Granted, in some cases there have been huge hiatuses on my end that were covered up because I had so many posts already scheduled, but that maybe just proves the success of the system.
I'm still trying out different systems for bringing a similar level of order and established structure to the rest of my adult life--vacuuming and exercising and staying on top of formal correspondance outside of work. Todoist worked for a little while, but wound up feeling too cramped, somehow. Print-out sheets were fun for a couple weeks but then became a hassle to work with. I've tried various setups in Trello, which I think will wind up being the long-term solution, in conjunction with Cold Turkey; I like the current one I'm using, but we'll see if it sticks.
I hope it does--the handful of weeks and months, here and there, where I managed to do things daily, in little bits, are like small oases surrounded by months and years of feeling off balance and struggling to get things done in a timely fashion instead of just marathoning through right before they're needed. Here's to 2020 being the year of self-discipline and lower self-inflicted stress (and subsequently cleaner bathrooms and floors).