What is happening to a unit to make it worn, spent or destroyed? And how are you hiding this process from your opponent? Are you calculating the damage that his fire has upon your unit but not telling him the outcome? This sounds like a road that I wouldn’t want to go down.
It could have some interesting applications.
A squad rolls 10 dice when firing less one die per marker. When the enemy makes a bayonet charge the defender rolls to see what the exact effect has been of the incoming fire. That is a crude approach; no doubt others would be able to refine it.