LMNT is great to use in a variety of situations - we receive feedback across quite a broad spectrum in that regard.
So here's the short answer: The most common usage is first thing in the morning, and about 30 mins prior to a workout, high-intensity activity, or when mental clarity is at a premium. A good thing to remember is when it comes to replacing lost electrolytes–preparing ahead of time is much better than chasing them afterward.
We certainly encourage folks to test out what works best for them, and to let us know–we are always eager for feedback!