- Conservation of Time: Time can neither be created nor destroyed (though it can be wasted).
- No Free Lunch: Accomplishing goals requires time.
- Burnout Limit: The (sustainable) amount of time available for work in each week is limited.
The burnout limit, on the other hand, is about the relationship of my professional life to my marriage, parenting, sleep, friendships, and self-care. Here, I estimate both the number of hours per week that are sustainable without pain, by looking at my "normal" work times, and also estimate the "surge capacity" that can be obtained if necessary by neglecting the other aspects of my life and calling in favors from my wife. I know that I most certainly will face surges during the year (e.g., paper and proposal deadlines, technical review meetings, parts of travel that aren't dual-use) and this capacity is also where I can try to catch up following surges in other parts of my life (e.g., sick child, doctor's appointments, etc.). So I'd better make sure my "normal week" planning is restricted to the sustainable level, or else every surge will be not just be a strain, but instead a serious crisis.
These two collide painfully in the principle of conservation of time. If I want more time to write papers, that means less time for something else. As my responsibilities for management and advising grow, that means my time for doing my own work on programming decreases. I can allocate my time around in many ways, but somewhere, somehow, I will have to say no to things, and conservation of time enforces that dismal fact upon me, forcing me to limit my wishful thinking to something that is more likely to be actually doable.
I have just finished going through this exercise for planning 2018, and it took 2.5 hours (budgeted in my schema to "self-organization" and "group organization"). The spreadsheet is very complicated, but I have made the numbers balance in a way that I know will not entirely match reality---but at least gets me started in a way that does not have predictable failures built in. I don't enjoy doing this, but doing it once a year has turned out to be important for me so far, and it's better than the closing my eyes and wishing for something that I know deep down cannot be true.
Physics is painful, eppur si muove.