but I keep no inventory on hand.
The parts you pay for can be considered and treated as a supply expense in you want, and you don't need to even mess with the COGS/Inventory section. However, you "can" use COGS to help you track what you pay for parts and the such. Is that what you desire to do?
I also don't maintain inventory, but only order parts "as needed". However, I utilize the COGS/Inventory section of the program for this, as I find it easier to keep track of the physical things I pay for, then immedidately re-sell to customers as part of the services I provide them.
