Our rule was always that if you bought 50 of something like food or ammo, you don't have to track how many you've used, we'll just assume you're well stocked and resupplying offscreen. The limit only comes back if the party is overtly cut off from resupply, like if they are shipwrecked on an uninhabited island.

This means you can easily have a limitless supply of normal arrows but still have to track your silver arrows, smoke bomb arrows, etc. Or you can invest the money to just have a limitless supply of whatever specialty item you think is worth the cost.