Mom, can I have a mental health day?
My kids were allowed to take one "Mental Health Day" per term in our house. I could usually tell when they needed it. It was typically in late October or early March. The newness and optimistic start to a new semester had worn off, and it seemed like an eternity until the end of the term. School at that point was just too much.
They weren't allowed to skip the work or be excused from a project, but sometimes they just needed a rest.
As much as I wanted them to learn to muscle through even when they were tired and follow through on their commitments, I also wanted them to learn to trust their bodies, minds, and judgment and tune into what they needed to sustain productivity.
Sure there were times they tried to slip in an extra day off. I was careful to keep track and I would kindly remind them that they'd already used their day.
I think in the end the Mental Health Day practice communicated to our kids that I trusted their instincts, I respected their needs, and that it's ok to responsibly follow through with your commitments in a different way than the original plan.