Does your character have chalk? Is it written on his character sheet? The level of detail given over to what characters have in their pockets and saddle bags varies tremendously from game to game. And that's fine. There is nothing objectively wrong with characters keeping track of every single quart of oil that passes through your character's hands, just as thee is nothing wrong with hand waving all non-magical equipment. In fact, when characters start interacting with the wish economy it is perfectly OK to handwave a character's minor magic items (we'll just assume that a 16th level Ranger has a wand of cure light wounds in his boot – it's seriously not worth keeping track of).