Time can cause people, goals, and other things to grow dull.
I find life in God to be the opposite; it is self-sharpening.
The reason for dullness gives us a clue for how to stay sharp. Hope's absence dulls. Hope's presence sharpens. Hope has built-in vision. Hopelessness is cataractical.
Destination sharpens. Distraction dulls.
Focus sharpens. Lack of concentration dulls.
Purpose sharpens. Pointlessness dulls.
Failure even sharpens. It is indifference that dulls.
Love for all people sharpens. Love for only those who already love us robs if we then have no room for others to enter our hearts.
A real God for real authentic living for very common people will always lead to a productivity which accounts for more wonder than any had originally imagined...Ephesians 3:20-21.