Yeah. The original Zelda had a mechanic where you could drink half the potion, or buy only half if you wanted. If were to have a game with an ID mechanic I think I might try that for potions.
I always wondered what it would be like if healing items could be used to heal you all the way and the leftovers would remain. So a Healing potion (23 oz) would probably be a one use item for a warrior but a wizard could take a sip every once in a while.
Now that I think about it - that's probably why we don't see it very often. If each healing item can be used several times, then the difference between low hp and high hp characters is less because your "effective max hp" is your base hp + number of uses found instead of base hp + number of potions found.
If you had 4 potions that heal 20 hp and you use them when you drop to 5 hp:
If you start with 8 hp then you drop to 5hp and recover 3hp per use: 8 + 3*4 = 20 total hp.
If you start with 30 hp then you drop to 5hp and recover 20hp per use: 30 + 20*4 = 110 total hp.
for a difference of 110 - 20 = 90 hp due to "wasted" potions.
If you had 4 potions of 20 ounces (=80oz) that heal 1 hp per ounce and you use them when you drop to 5 hp:
If you start with 8 hp then you drop to 5hp, recover 3hp (77oz left), drop to 5hp, recover 3hp (74oz left) ... etc = 8 + 4*20 = 88 total hp.
If you start with 30 hp then you drop to 5hp, recover 25hp (55oz left), drop to 5hp, recover 25hp (30oz left) ... etc = 30 + 4*20 = 110 total hp.
for a difference of 110 - 88 = 22 hp due to initial differences (30 - 8 ).
So, for healing type potions at least,
having multiple uses that remove the concept of "waste" means that the difference between low hp and high hp characters is sort of lost. There's still the lost turns when quaffing potions though.
Although maybe you want to lessen the difference between low and hp characters.