The Inventory module tracks your parts and supplies - your consumables, that are used to repair and maintain your assets. 
 

Parts listed in the inventory module will track:

• Current quantities
• Preferred stocking levels
• Current price (and pricing history)
• Vendor information
• Assets using the parts in question 

EVERY part that you use, can be listed in the Inventory module - even if you don't keep a particular part in stock.  The Inventory module will help you differentiate between:
 

• Stocked Parts (ones you keep on the shelf)
• Non-Stocked Parts (ones you add as needed, but don't keep in your shop)
• Tires (a special designation of parts, to track rotation & meet DOT requirements)