I have a standard equipment accounting methodology I use, which in consider seperate from how much detail is tracked. The system is easy, and makes for clear record-keeping, regardless of how detailed you are.
On the inventory section of your char-sheet, record each item prefaced with a quantity, as such:
10 Gold
12 Silver
1 Longsword
1 Winter explorer's outfit
1 backback
I f you want to document what's stored in the backpack specifically, put those items beneath the backpack entry, indented (pretend the _ are indents):
1 Backpack
___1 spellbook
___1 flint and tinder
___50' silk rope
Let's assume you've done this on a computer, and printed it out. During the game, do NOT write on this sheet. You'll just mess it up if there's a lot of finding and losing of gear. Instead, on a piece of scratch paper, when something is added to you inventory, such as 50 gold, write it as:
+50 GP
When you spend 20 gold, and find some Splint Armor +2, write it as:
-20 GP
+1 Splint Armor +2
The minus shows it left your inventory, the plus shows you added it. In the case of money, unless you're likely to run out, you don't need to add it all up until after the game. If the GM hands out XP during the game, I'll write that on the list as well:
+300 XP
The reason for keeping a seperate sheet, is that until the end of the game, you don't really know what stuff you got is going to stay. Therefore, don't bother messing up your sheet. This also simplifies dealing with money. Assuming you have a fair amount (or can eye-ball it), you don't need to keep a running total.
Now despite my potentially detailed accounting system, I don't necessarily want to track or enforce certain details. For instance, I'm find with inventory just describing entire outfits, or assuming the Spell Component Pouch has all the common components the wizard will need. I'm also not as interested in having the player deduct arrows that get shot.
Exceptions to this, particularly for food and ammo: if the situation is about scarce resources (stuck in the desert or a siege), than tracking this stuff is about making the players manage their limited resources (and potentially running out). But in a generic adventure, that's not too important, especially at higher levels where the PCs generally have the funds to keep stocked and thus it could be assumed they did so.