I think it's important to keep challenging yourself and not get too comfortable.

The Romans would never have found time to conquer the world if they had been obliged first to learn Latin.

"Maybe you can afford to wait. Maybe for you there’s a tomorrow. Maybe for you there’s one thousand tomorrows, or three thousand, or ten, so much time you can bathe in it, roll around it, let it slide like coins through your fingers. So much time you can waste it. But for some of us there’s only today. And the truth is, you never really know."