I'm a millennial. The programmers and artists I employ are 100% millennials. Here are some things that prevent burnout and also make solid business sense:
1) Work on projects that have a fast turnaround.
How does it avoid burnout? It keeps things fresh. The beginning of a project is the most creative time. You're building something that the world has never seen before. We try to have beginnings as often as possible.
Why is it good for business? It's easy for projects to grow beyond their scope. You have to fight this or you end up in a death pit of diminishing returns. It's bad for morale, and it's bad for business at a startup. Lots of complete, tidy projects is better than one that drags on forever.
2) Work together. Don't be lonely
How does it avoid burnout? I go crazy if I have to work on something by myself for more than a couple of hours. Human beings are naturally social. I think millennials reject the kind of lonely, "cubicle culture" that has become the stereotype for corporate culture.
Why is it good for business? Research shows that two programmers who work together make fewer mistakes and are more productive that two programmers working alone.
3) Make visually stunning things. Don't be boring.
How does it avoid burnout? My company makes video games. And we make them as visually stunning as possible. Lots of color. Lots of feeling. Things that demand your attention. If we don't like the visuals, the whole project stops feeling rewarding.
Why is it good for business? Good art and good design are easy to market. It's as simple as that. We all know that a picture is worth a thousand words. Our customers also happen to be millennials, so this works out well.