What you know doubles when you teach it and rots when you hoard it.

Explaining something exposes every soft spot in your understanding, which is why teaching is the quickest way to actually learn. Kept to yourself, what you know stays the shape it was on the day you picked it up and slowly goes stale, since nothing is pressing on it. Hoarding also tends to grow from a fear that the knowing is the only thing making you valuable.

Teach one thing this week to someone who does not know it, out loud and unpolished. Notice where you stumble, because that is your real gap. Fill it, then explain it again.