ItemAge

Records how long you have had an item and displays it in your bags/bank and/or tooltip. Stacks of equal items will have separate ages. Notes for items can be attached to tooltip. Counts how many times an item has been on auction.

New in ItemAge v0.12
[fix] Bug that would in certain cases cause the auction-count to not update
[fix] Certain settings would cause wrong age

The addon
I made this addon because my bankers are always loaded with items and I loose track of how long I have had the different things in my bags. ItemAge will keep track of items' ages for you. It tracks individual items/stacks, so two equal items or stacks may (and will) have different ages.
The age can be displayed directly on the item in your bags, and/or in the item's tooltip.

Auction
ItemAge will also track how many times you have put an item up for auction. This is displayed in the tooltip alongside the item's age.

Notes
You can attach your own notes to items. Even separate notes for equal items. Personally, I use this facility remember how much I payed for an item and sometimes where I got it from. A nice feature if you for example buy stuff from the auction-house just for resale.

To use notes, you must set up a hot-key in WoW's "Key Bindings" from the game's option-menu. Find the section for ItemAge near the bottom, and set a key for notes. When this has been done, you can press this key whenever you mouse-over an item to open a dialog-box where you can enter text. The entered text can be as long as you like.

Supported items
Most items in WoW is trackable. However, items you have bought from a vendor will basically never be trackable. This is due to how WoW generates the items. A vendor-bought item will be generic and undistinguishable from another vendor-bought item.
There are also some add-ons out there that will change all the in-game item-links to such a degree that it removes the Blizzard-supplied trace-data. If this is the case, it will make most (if not all) items untrackable.

Options
The options are available with the command "/age". These are:
bags -> Bag-display on/off
bank -> Bank-display on/off
gbank -> Guild-bank on/off
tooltip - Display in tooltip on/off
Note that guild-bank does usually not show anyway because of WoW's handling of these items. Some items does however display.

ItemAge can also be assigned a key so you can press a key to show/hide the display whenever you want to check the ages. This is very handy for non-banker toons, and can be assigned from WoW's standard key-binding interface.

Stacks of items
Many items are stackable, like leather and cloth. If you already have a stack that is not full and you receive one more item, WoW will merge the new item into your old stack. The "new" stack will be registered with the age of the old stack.
This is particularly important to notice when retrieving unsold items from the AH and you already have a half-full stack in your bags of the same item.