However it is that you track it, my suggestion would be that
you track it.
I am — admittedly — a bit anal about this in the games that I run (resource allocation being a big part of the game, I mean). But I realize that it might not be everyone's cup of tea. Asking each of your players to be meticulous would cause a few problems:
1) Some of the players won't be as meticulous as you would like.
Example: A post from one of your players uses some sort of expendable (bullet, potion, whatever).
- They, not being as meticulous as you would prefer, might not adjust anything on their sheet.
- A few days go by before you sum up the action and remind the player to adjust their inventory.
- A few days go by from there and then the player posts again (but they do not update anything)
- A day or so goes by from there and having seen that the player posted, you remember to check their sheet ... only to find that it is unchanged.
- Wash, rinse, repeat.
Quite a few of these instances will occur in tandem and many of them will overlap (multiple players, multiple posts, etc).
It's tough to put that genie back in the bottle.
2) Not every player enjoys that level of detail in a game. You'll be shutting the door to a large number of folks at the very outset. Or worse yet ... great players join, only to discover that the bookkeeping is not fun and they withdraw.
3). Even if you
did have folks that were good at adjusting their stuff ... how would you even know if if was being done? If you checked the sheet and it had like ... half a clip remaining. What's to say that the next time the item gets used (say, weeks or months from now) that you would even remember that the item had half-a-clip remaining before this next use.
A possible way would be for you to make a note of where stuff is at ... but if you're going to go through all that mess ... why make the players do it at all?
tl;dr
For games where resource allocation matters, I track the trackable stuff for my players in a public thread. If I need to, I enclose the item in a 'private to' message so that other folks aren't privy.
For games where it doesn't, I liberally apply handwavium to stuff like this (and reserve the right to take it away when the story could benefit from a twist, like a complication from Fate if you are familiar with that game).