How do you know what matters?

Patrick McKenzie had a great tweet the other day:

Don't do things that don't matter, as an individual or as an organization. Doubly so in the second case, because you'll evolve an entire infrastructure enthusiastically supporting and dependent for their continued livelihood upon the thing that doesn't matter.

It's hard to know what "what matters" and what doesn't. Lately, I've been thinking about that as free time will shift quite dramatically. Things that matter would move me closer to my goals and fulfill me. That can be hard when those goals change too.

I think a system to help me evaluate will be more useful here, so that's what I'll spend some time thinking about.