5 years is also a pretty arbitrary span to go with. You could smoothly discount future time savings instead, but then your discounting curve is arbitrary.
The most rigorous way to go would be to set some kind of future goal, and then work your way backwards to find some kind of statistical description of the shortest path there, or else set some kind of future metric at a specific time and find the path that maximises it. This is pretty much how you design your investing portfolio, just with money instead of labour.
5 years is also a pretty arbitrary span to go with. You could smoothly discount future time savings instead, but then your discounting curve is arbitrary.
The most rigorous way to go would be to set some kind of future goal, and then work your way backwards to find some kind of statistical description of the shortest path there, or else set some kind of future metric at a specific time and find the path that maximises it. This is pretty much how you design your investing portfolio, just with money instead of labour.