Easy hack that is very helpful but people often fail to do it: Do things in the exact same order every time you do them when trying to get better at something. This instils habits faster and saves you cognitive load as you are able to operate on autopilot. You also are able to more easily ballpark potential efficiency improvements. Basically, the first step towards refactoring is to actually algorithmatize your task.
Also might want to take into account the probability that your improvement will persist in order to accurately calculate the expected time savings.
Is there any reason this doesn't also naively enable conversion to money? (If you make $N/hr should you be willing to spend $N in lieu of one hour?)
I used to do this conversion when I was contracting at hourly rates and my time was the bottleneck: should I fix the toilet myself or call a plumber? It no longer makes sense on a 9-5 job. The fungibility options (have I used this term right?) are different.
There was an article a while back about how time doesn't convert directly to money, at least in terms of an hourly wage. It's essentially the same problem that shminux mentioned.
It's still in principle possible to put a monetary value on marginal increases in available time, though, and might be practically possible in some situations (like shminux's contract work). In cases like that, one could convert the table to money.
I wonder if you could get a time/money conversion with a revealed preferences sort of method - listing all the tradeoffs you already make and looking for a pattern. It seems like it would at least be useful for noticing if you're being "money pumped" (although consistent does not necessarily equal correct, and time does not necessarily always have equal value).
There was an article a while back about how time doesn't convert directly to money, at least in terms of an hourly wage.
Unless you put yourself in a situation where you can work any time you want, and earn hourly incremental dollars.
I was working two contract jobs at the same time, as I transitioned from one to another. Both sides had an attitude of "give me as many hours as you can". I did a lot of work, because making X dollars and hours usually seemed like time better spent than what I would have otherwise done.
It's hard to manage that kind of situation, but I should find at least something similar - some kind of project or side business where the money was fairly linear and incremental with time.
What jobs were these, and did they pay well? (Of course, feel free to not answer if you're concerned about privacy or similar.)
Another gem from xkcd: Is It Worth the Time? It visually answers the question:
How long can you work on making a routine task more efficient before you're spending more time than you save?
Of course, he's not the first person to ask this question, but the visual is handy. Note that the times are calculated assuming you'll save the time over five years.
For example, I've been pondering how to shorten my showers. If I can shave off 1 minute daily, I should be willing to invest up to (but no more than) an entire day to do it. If I think I can shave off five minutes preparing my breakfast, I should be willing to spend up to six days attempting to do so.