Reliability-Centred Spares (RCS) is "an approach for determining the level of spare part inventories based on through-life costing and the requirements of the equipment and maintenance operation that the inventory supports".
Applied correctly, Reliability-Centred Spares yields the following benefits:
RCS uses through-life costing to ensure that every pound invested in spare parts is spent where it will do the most good. RCS answers the question of whether money should be invested in spares in order to reduce downtime costs in the future.
All parties (including accountants!) relate to RCS as it determines spare part levels without relying on gut feel or subjective judgment.
Substantial savings can be made by applying RCS to expensive, slow-moving critical spares. Vendor stockholding schemes may also be evaluated against the alternative of holding stock locally.
Traditionally, stock levels were determined by a mixture of gut feel, manufacturer's recommendations and subjective judgments of service level. None of these addresses the fundamental question - "is it worth buying a spare part, and if so, how many?"
RCS can be applied at any time in an asset's life-cycle (ie before buying any spare parts or when an asset has been in service for some time).
It can be applied selectively to the spares inventory by using the pareto principle since a small number of items are usually responsible for a large proportion of inventory value and/or could incur large production losses in the event of a stockout.