There are valid reasons for a company to want to lease their assets...
...Poor fleet management shouldn't be one of them
There are three distinct fleet leasing relationships:
Finance Lease This relationship (usually with a bank or finance company) is a valid way to finance your assets, structure your cash flow, and tax position.
Fleet Management Lease (ARI, Enterprise, Leaseplan, etc) This relationship is a hybrid version of a finance lease with "value added" services to aid in acquisition, operation and disposal of fleet assets.
Full Service Lease This relationship is a complete outsource of the fleet management process. It offers the most robust service offerings and least risk to a fleet operator.
Many companies enter into Fleet Management or Full Service Lease relationships because they lack expertise and internal controls.