I can't agree more, we live for a short period of time and a healthy life is definitely the best way to enjoy the time we have.
I primarily motivate myself to stay healthy with Apple Watch achievements. Based on your activity you receive some awards. There are many kinds of awards and sometimes you can earn special awards on special days like the “Earth Day Challenge".
In addition, I share my activity with a couple of friends and it's fun to beat your friend's daily goals.
Speaking of audiobooks. Do you know about https://www.overdrive.com? Basically, you can borrow audiobooks and ebooks from your local library. They have a wide selection and you can request a book if they don't have it. This can save you money if you listen to a lot of audiobooks.
Yes! Overdrive is how I found Daniel Suarez, my favorite Cyber Punk author. I haven't used it for a while though since many of the books I listen to aren't available through my library.