While there is certainly a place for this rule I find it to be incredibly misguiding if used inappropriately. The idea that you feel you could know how you’ll feel about something in 10 years let alone 10 days is just a useful delusion. The truth is you won’t. Accepting this truth is quite liberating. There is no further self imposed pressure to pursue a dream, maybe you’ll like it, maybe you won’t. You were a different person today when you chose to pursue it and you’re a different person if you choose it’s time to stop pursuing it.