a receipt (= bill of sale describing the assets transferred, the purchase price, and a payment record) is a really nice thing to have when the auditor arrives. keep it with the contract.
outsourcing mode means that you can get a bunch of assets off you books; sell them to the supplier who will then lease them back and put them on a structured refresh cycle.
somebody has to do an inventory to find out what’s out there. the existing inventory system should have an audit process attached to it and a sampling approach can give you a good idea how accurate the legacy inventory management process is.