The best proverbs say in one line what it would take a page to explain. In a single short, powerful line, they sum up a huge idea.

For instance, I love the proverb “A stumble may prevent a fall.” I wrote a lot about that proverb in Better Than Before, my book about habit change, in the chapter on the Strategy of Safeguards. It perfectly sums up the idea that sometimes, a small error can save us from a bigger, worse error. Getting a bad grade on a paper in sixth grade can save us from getting a bad grade on a paper in eleventh grade.

I also love the proverb, “When the student is ready, the teacher appears.” I wrote about that proverb in my book The Happiness Project. It’s uncanny how often that once I’m ready to learn about something, someone turns up to help me.

Lately, I’ve been thinking a lot about another proverb I love: “The best time to plant a tree was twenty years ago. The second best time is now.”

It’s a great reminder that we shouldn’t spend our time wishing we’d been wiser in the past or had more forethought. We can’t do something twenty years ago.

But we can do something now. Now maybe the second-best time to start, but it’s the time that we can start – and we can remember that in twenty years, we’ll look back and wish we had started.