The world is filled with so many variables, it's impossible to know what investment - of time, energy, money - will reap you the most rewards. This is why it's important to follow this simple rule: diversify first, concentrate second.
For example, let's say you want to start a business. You don't want to start by thinking up a cool product that people will buy. You want to start by brainstorming multiple product ideas - 5-10.
Then as quickly and inexpensively as possible, you want to test those ideas. Create quick, cheap prototypes and put your ideas out there. See which ones do well and concentrate your business on those winners, cutting the losers.
This rule can be applied to all sorts of situations. Are you looking for a relationship? Date multiple partners at once and see which one gives you the most happiness. Cut the others and commit to the best one.
Are you looking for a place to retire? Do long, but cheap vacations in a bunch of different locations - places within your budget. Choose the one or two that really offer you the best experience.
Trying to find a good company to work for? Interview with a few different companies. Really get to know them and see how work would be. Choose the one company that excites you the most.
Trying to find a career path? Research a bunch of different career paths that you think would be exciting. Watch videos, if possible, volunteer or intern there. Choose the one that gives you the most excitement.
I could go on and on about how to use this rule. The point is that life is too short to commit to one thing from the get-go. The more information you have, the better choices you can make about where you invest your time, money, and energy.