If PCs are winning fights without using their potions and scrolls, then they're doing it right. They should keep winning fights without depleting non-regenerating resources. Better to win and still have the scroll/potion in reserve, than to win and NOT still have it in reserve.
If PCs are losing fights, resting, resuming the offensive, and eventually succeeding, then they're still doing it right.
If PCs get a TPK because they didn't bother to track and apply all their resources, then... did they have fun?
If the players enjoy TPKs more than they enjoy using all the PC's resources to win, then they're STILL doing it right.
If you object to any of these scenarios, then YOU have an unmet need. Do you expect your players to meet that need, or to help you meet your own needs?