If you've ever looked at a project and thought "I have no idea how many hours I've put into this," you need HOFA ProjectTime in your life.
It's a free plugin that logs your session time automatically. Drop it on your master track, and it starts timing the moment you open the project. Pauses when you stop playback. Picks up right where you left off next session.
Here's the move: save it to your DAW template so it's loaded on every new project from day one. Open your session, check your hours, and make sure you're actually moving forward and not just spinning your wheels on the same 8 bars.
The 20-Hour Rule only works if you actually know when you've hit 20 hours. This is how you know.
Track it. Honor it. Finish it.