WLC is a technique that takes account of the total costs of purchasing a given item over a specified period; not simply the cost of buying (or leasing) an item but also operating, maintenance or running costs in addition to costs associated with end of life (disposal costs). These costs can be used to inform decisions about which of the means of meeting the requirement offers the best value.
WLC can be applied to many purchasing decisions but is most appropriate to capital purchases (vehicles, equipment, buildings etc.) and it is just as applicable to leasing and hire agreements.
WLC guidance document