Hmmm, so arrows are like beer at a party. You think there is plenty then all of a sudden, all gone.
The obvious super duper big problem is when the unlucky archer runs out of arrows after like 4 shots.
Player: "What? While setting up our elaborate ambush I didn't notice that I only had 4 arrows left?"
DM "Err, um... actually, in your excitement you put the quiver on upside down and only 4 managed to get stuck. You trampled the rest to bits while watching the enemy army approach."
-or-
DM- "Actually, there are like 16 arrows left in the quiver, but the apprentice who finished making them forgot to put the heads on them before filling up the quiver. You're lucky I let you shoot the good 4 before running across the bad ones."