Another suggestion, somewhat related, is that you should focus on the activities that have the highest expected monetary reward. Prices are a valuable signal that represent the collected wisdom of a lot of reasonably rational actors. They should be an important part of your calculation of how to spend your time. In other words, if someone is willing to hand you a pile of money to do something, that probably means they have thought long and hard about it and consider whatever they want you to do to be very valuable. You should think long and hard about it before you decide that some other activity that no one is willing to pay you anything for is actually more valuable.

hmmm - not necessarily. With this heuristic, the common wisdom says it's much more important that we spend our time working on the docks... or hedge-fund twiddling.. rather than teaching children.

Socially I'd consider the latter far more important, both short and long-term, but more powerful unions have made the former job better-compensated, and the middle-one... well they grabbed that wealth for themselves despite the long-range utility to the rest of the species.

So yes - a heuristic with some benefit, but keep in mind its many failure modes.