Welcome to another issue of Mind Macros - I hope you find something of value.
"Shortest Processing Time: always do the quickest task you can. Even if you don’t have impatient clients hanging on every job, Shortest Processing Time gets things done. Again, there’s no way to change the total amount of time your work will take you, but Shortest Processing Time may ease your mind by shrinking the number of outstanding tasks as quickly as possible. Its sum-of-completion-times metric can be expressed another way: it’s like focusing above all on reducing the length of your to-do list. If each piece of unfinished business is like a thorn in your side, then racing through the easiest items may bring some measure of relief.
"When a task’s starting time comes, compare that task to the one currently under way. If you’re working by Earliest Due Date and the new task is due even sooner than the current one, switch gears; otherwise stay the course. Likewise, if you’re working by Shortest Processing Time, and the new task can be finished faster than the current one, pause to take care of it first; otherwise, continue with what you were doing.
"If you don’t know when tasks will begin, Earliest Due Date and Shortest Processing Time are still optimal strategies, able to guarantee you (on average) the best possible performance in the face of uncertainty. If assignments get tossed on your desk at unpredictable moments, the optimal strategy for minimizing maximum lateness is still the preemptive version of Earliest Due Date—switching to the job that just came up if it’s due sooner than the one you’re currently doing, and otherwise ignoring it. Similarly, the preemptive version of Shortest Processing Time—compare the time left to finish the current task to the time it would take to complete the new one—is still optimal for minimizing the sum of completion times.
"In fact, the weighted version of Shortest Processing Time is a pretty good candidate for best general-purpose scheduling strategy in the face of uncertainty. It offers a simple prescription for time management: each time a new piece of work comes in, divide its importance by the amount of time it will take to complete. If that figure is higher than for the task you’re currently doing, switch to the new one; otherwise stick with the current task. This algorithm is the closest thing that scheduling theory has to a skeleton key or Swiss Army knife, the optimal strategy not just for one flavor of problem but for many. Under certain assumptions it minimizes not just the sum of weighted completion times, as we might expect, but also the sum of the weights of the late jobs and the sum of the weighted lateness of those jobs.” — From Algorithms to Live By by Brian Christian & Tom Griffiths (view my three takeaways)
Most of us have an almost endless list of things we should, could, and want to do. Even from week to week, the list of priorities can overwhelm one's sense of organization. What should we tackle first? What is most critical? What is the optimal way of sorting our responsibilities? Earliest Due Date and Shortest Processing Time are algorithms that can handle the sorting criteria to get us back on course.
If our boss provides us with a list of tasks at the beginning of each week, sorting them based on the due date, then the shortest processing time provides us with the best strategy. Unfortunately, to-do list applications cannot handle such calculations, and a simple spreadsheet may be more effective. 
A skeleton key (see above) approach works best when we spend our weeks in the trenches, responding to tasks and putting out fires as they arise. It can be difficult to decide which task should take precedence in these situations, as time is of the essence. Within the spreadsheet, we can assign a number out of 10 to represent a task's importance and then estimate a completion time. The order is established by dividing the task's importance by it's estimated completion times and sorting them from highest to lowest. As new responsibilities emerge, we can update the spreadsheet to determine the most effective task management strategy.
"The psychology professor Robert Boice spent his career studying the writing habits of his fellow academics, reaching the conclusion that the most productive and successful among them generally made writing a smaller part of their daily routine than the others, so that it was much more feasible to keep going with it day after day. They cultivated the patience to tolerate the fact that they probably wouldn’t be producing very much on any individual day, with the result that they produced much more over the long term. They wrote in brief daily sessions—sometimes as short as ten minutes, and never longer than four hours—and they religiously took weekends off. The panicked PhD students in whom Boice tried to inculcate this regimen rarely had the forbearance to hear it. They had looming deadlines, they protested, and couldn’t afford such self-indulgent work habits. They needed their dissertations finished, and fast! But for Boice, that reaction just proved his point. It was precisely the students’ impatient desire to hasten their work beyond its appropriate pace, to race on to the point of completion, that was impeding their progress. They couldn’t stand the discomfort that arose from being forced to acknowledge their limited control over the speed of the creative process—and so they sought to escape it, either by not getting down to work at all, or by rushing headlong into stressful all-day writing binges, which led to procrastination later on, because it made them learn to hate the whole endeavor.
"One critical aspect of the radical incrementalist approach, which runs counter to much mainstream advice on productivity, is thus to be willing to stop when your daily time is up, even when you’re bursting with energy and feel as though you could get much more done. If you’ve decided to work on a given project for fifty minutes, then once fifty minutes have elapsed, get up and walk away from it. Why? Because as Boice explained, the urge to push onward beyond that point ‘includes a big component of impatience about not being finished, about not being productive enough, about never again finding such an ideal time’ for work. Stopping helps strengthen the muscle of patience that will permit you to return to the project again and again, and thus to sustain your productivity over an entire career." — From Four Thousand Weeks by Oliver Burkeman (view my three takeaways)
There’s a common tendency that runs contrary to radical incrementalism. The approach is to adopt the most extreme version of a habit rather than something more manageable. What a developed habit might look like after six months is our starting threshold. Instead of reading a page a day, it's setting a goal to read a book per week. Rather than exercising twice a week, we must exercise six times a week. It's not enough to start small; we must go all in on the idealized version of the habit. Sometimes we attempt to perfect habits we have yet to start, holding ourselves to such high standards that we never begin.
If we're trying to build a habit of reading regularly, a book per week is daunting. However, reading a page daily is more approachable; it's almost so simple we cannot fail. Stupidly simple is the goal to aim toward when beginning the process of behavioral change, as James Clear explains in Atomic Habits:
"Whenever you want to change your behavior, you can simply ask yourself: How can I make it obvious? How can I make it attractive? How can I make it easy? How can I make it satisfying?"
After committing to one page a day, not only will we become regular readers, but we'll often cruise far beyond it. We've made the process easy and enjoyable rather than a speed-reading exercise to clear our page quota for the day.
Radical incrementalism optimizes for longevity rather than the resulting burnout from short-term sprints. As habits increase in value the more they are performed; the majority of benefits compound over months, if not years. Four workouts throughout a week won't move the needle in any meaningful way and in isolation, seems futile. Yet, zooming out to a full year, and the 208 completed workouts might be life-changing. Clear puts it best, writing in Atomic Habits that "you should be far more concerned with your current trajectory than with your current results."
The analogy of the stonecutter from Jacob A. Riis is a worthy motto to remind ourselves of when our discipline is wavering:
"When nothing seems to help, I go and look at a stonecutter hammering away at his rock, perhaps a hundred times without as much as a crack showing in it. Yet at the hundred and first blow it will split in two, and I know it was not that last blow that did it, but all that had gone before."
"Not-knowing is true knowledge. Presuming to know is a disease. First realize that you are sick; Then you can move toward health."
"Anyone who has not groomed his life in general towards some definite end cannot possibly arrange his individual actions properly. It is impossible to put the pieces together if you do not have in your head the idea of the whole… The bowman must first know what he is aiming at: then he has to prepare hand, bow, bowstring, arrow and his drill to that end. Our projects go astray because they are not addressed to a target. No wind is right for a seaman who has no predetermined harbour."
Thank you for reading,
 To-do list applications can sort by due date and predefined time increments by using tags and smart lists. We could assign tags such as 5m, 15m, 30m, 60m, and so forth. Then a smart list could pull these tasks into a single list, sorted by the due date. To my knowledge, the skeleton key approach would not work unless you manually divide the task's importance by estimated completion time, defeating the algorithms' time-saving purpose. I imagine someone somewhere in the world uses a spreadsheet as their task management system, but it's far from ideal. The best-case scenario might be to copy tasks at the beginning of each week into a spreadsheet to make the appropriate calculations.