Expensing versus Capitalization. This website discusses a case of FedEx versus the IRS with regards to expensing maintenance costs versus capitalizing them. The IRS had claimed that these costs

were capital expenditures... which must be amortized. FedEx claimed that the amounts paid... were ordinary and necessary business expenses... which were currently deductible.

The article explains the court's decision for finding in FedEx's favor and allowing the items to be expensed, versus capitalized:

(Since the items) did not materially increase the value of FedEx's aircraft, did not appreciably prolong the life of FedEx's aircraft, and did not adapt the property to another use. The (items in question) merely maintained the (aircraft) in an ordinary efficient operational condition. As such, the expenditures... were incurred as ordinary and necessary business expenses incidental to the maintenance of FedEx's aircraft.

(Submitted by P. Timmerding)