As Pirog mentions oft-

Ammunition needed for the artillery weapons (bows) in conjunction of deterioration of the bladed weapons.
I also heard nails being introduced so the concept of individual tiny items would work well. If nails are produced in large amounts, so should ammo:
Just an example:
For 10 Crossbow Bolts: 50 grams of steel, 200 grams of iron
For 10 Warbow arrows: 50 grams of iron, 500 grams of wood
For 10 Hunting Bow arrows: 50 grams of stone, 500 grams of wood, or 50 grams of small bones, 500 grams of wood.
If nails are Individually made, I guess so should ammo and probably from a similar machine:
Bolt: 5 grams of steel, 20 grams of iron
Warbow Arrow: 5 grams of iron, 50 grams of wood
Hunting Bow opts: 5 bone or 5 stone, 50 wood.
Oh and for sling shots and similar weapons as well. Perhaps for them, they could have a handicap removed, like a slower deterioration rate then blades, or pump up the power a bit.