My oil light started coming on, giving me a real scare once. Failure to start turned out to be from a damaged starter, expensive but easily replaced, rather than frozen crankcase from oil depletion, though I started looking at new cars just in case. I set an oil schedule. On the 15th and 30th of every month I would check the oil level in my car. Had to add a quart last time. It takes minutes and avoids tzuris.
My financial statements have a way of accumulating. I set two filing days a month: the 11th and 25th. My financial position is fortunately good with professional oversight but I really should look at it more than I do. Now its gets done on the 17th. My Medscape submission takes two dates, the 20th to select a topic and the 29th to submit. On the 20th of each month I make a Jewish donation. All arbitrary self-imposed deadlines.
Sometimes I need to divide a week rather than a month. Sunday my pills get set out. Wednesday shabbos dinner gets taken from the freezer. Thursday mini-challot get taken from the freezer and I review four parsha commentaries. I recover from exercise on the days divisible by 3 and omit Facebook and Twitter on the days divisible by 4. My weight gets taken and waist circumference measured first thing every Monday morning. Every Wednesday night, though occasionally Tuesday if convenient, I enter my weekly health log of Wt, Waist, BP, Treadmill progress, and how I feel.
Except for the biweekly filing perhaps and the Parsha review, no one periodic task takes more than ten minutes, and some take zero as they are omissions of otherwise daily activities. And I've been mostly faithful about following through. All are finite points in time with finite tasks which impose structure on the many things I need to do or want to do that don't have specified times. Those don't always get done.