Burn Out or Rust Out?

Amy Carmichael, missionary to India, made it clear that she "would rather burn out than rust out." This attitude has often been interpreted in Christian circles as the life of a "true believer". Though, it should be noted, that it is not only Christians who adopt this as a mantra to live by. In fact many attribute the notion of burning out over rusting out to rocker Neil Young and his song "Rust Never Sleeps." Whether specifically Christian or not, burning out represents a passionate and dedicated pursuit of something, even if it leads to exhaustion, while rusting out symbolizes a life of inactivity and stagnation.
Of course generations of Americans did subsequently burn out pursuing all sorts of ideals, Christian or otherwise, with all sorts of attendant consequences (burnout, broken families, etc...). This then gave rise to the pendulum swinging back the other way, boundaries being set, Netflix dates kept, and the notion of rusting out pushing to the fore. In this anti-burnout world, busyness is no longer a virtue, even if it comes at the cost of no longer serving others.
You may be thinking that those are broad generalizations, both of two ways of living and of past or current times, and of course you are right. My point in setting the table this way is more or less to lay out the extremes as we consider this little vignette from Mark 6:30, 31, "The apostles returned to Jesus and told him all that they had done and taught. And he said to them, “Come away by yourselves to a desolate place and rest a while.” For many were coming and going, and they had no leisure even to eat."
Here we see both sides of this pendulum. On the one hand, the disciples and Jesus were, as they often did, working and serving to the point of exhaustion. While on the other hand, Jesus is setting a boundary, calling his disciples away to rest and re-create themselves in fellowship with him. How are we to interpret this or apply it?
I suppose there is a lot that could be said, and we will be looking at the whole of the passage from Mark 6:30-44 this coming Sunday. For now, let me plant this thought and hopefully some fodder for reflection. Many want to talk about balance when discussing burning out or rusting out. However, if by balanced we mean a perfectly aligned, tepid lifestyle, that never gets too hot or never gets too cold, I think we are missing the mark. But if by balanced we see, as I think we see in Jesus' own life, intense periods of laying down your life for a (Gospel) cause to the very point of exhaustion and alternate times of intense, intentional retreat, to rest and re-create with our Savior (Sabbath anyone?) -- then I can get on board. As I said, I hope that there is some fodder for personal reflection there?