A good question outlives most answers.

Answers are fixed to a moment, and questions keep working after it. An answer is only good while the facts behind it hold, and facts move, so most answers quietly expire. A real question is a tool you can point at a new situation years later and still get something back. That is why the same few questions keep turning up in every field.

When you learn something this week, write the question it answers rather than the answer. Carry that around instead. See whether it still opens something up in a subject that has nothing to do with where you found it.