We get what we invest in. The time we spend comes back, with interest.
If you practice five minutes of new, difficult banjo music every day, you'll become a better banjo player. If you spend a little bit more time each day whining or feeling ashamed, that behavior will become part of you. The words you type, the people you hang with, the media you consume…
The difference between who you are now and who you were five years ago is largely due to how you've spent your time along the way.
The habits we groove become who we are, one minute at a time. A small thing, repeated, is not a small thing.
[And the same thing is true for brands, organizations and movements.]