Half-Drank Potions

I feel that a useful gameplay feature that would make brewing and potion use more mainstream would be the ability to drink only half of a potion if you so choose. For example, say you have yourself an Instant Health potion. With this new ability, you would be able to drink half if you wanted and only half of the potions effects will be applied. After drinking half of the potion, you will be left with a Half-Drank Instant Health Potion, that you could use later. You could also drink all of it at once if you wanted to, and the potion would behave normally. If you had a potion that was time-based and not instant, such as a Fire Resistance potion, drinking half would make the potion last half as long.