avoiding burn-out

Monday night was an intense class of kata, stance work, and knife defenses. Last night was white belt basics, due to a new member in attendance.
And I loved both.
The change of tempo suited me well last evening, especially as I've had kata coming out the gi lately, and a chance to step back and reacquaint myself with the fundamentals of jui-jitsu was perfect. I worry when the simple aspects get lost in too much advanced technique and I am always happy to return to the basics to make sure these foundations are still intact. Or at least close to it.
As I've alluded to before, rust can form quickly, and bad habits may easily return.
I also feel intensity is a great aspect of training--going hard after what you want can be amazing--but burn-out is never far behind without a pendulum shift. I think last week, this burn-out was getting close.
But today I feel ready for more.