When materials are needed, it is essential that they are available either from the MRO inventory or from a supplier in a timely manner. The goal is to operate at full capacity, maximizing the need to have zero downtime, and maximum production output. Maintenance means capacity assurance which in general terms means that repair work becomes seamless and a goal of attaining 85 percent planned work becomes a way of doing business. The goal of the storeroom is to support maintenance and operations by being able to supply parts by the date required. Cost prohibits large inventories and the facility must learn to run lean and hold inventories at a minimum. Suppliers are accountable for meeting the due date indicated by the planner and or the requestor. If there is a problem and the delivery date is going to be missed, the supplier must contact purchasing to let them about the delay and provide a new date when the material will be arriving. Purchasing and the storeroom must communicate with the planners when parts are going to be delayed so planned jobs can be adjusted. This type of communication is essential between departments and suppliers, surprises are not an option. Expected service levels of MRO parts:

• Critical or insurance spares (available 100 percent of the time) are spares used on critical components of an equipment asset. The MRO parts identified as insurance spares are required to be in stock to receive reduced insurance premiums and hedge against lost production downtime insurance claims.
• Components to insurance spares (98 percent availability) are parts used in critical equipment and equipment components. The use is unpredictable since the mean times between failures are unpredictable. The result of not having insurance parts in stock can cause extended downtime and major losses of production.
• Standard replacement parts (95 percent availability) parts that can be used on more than one component or piece of equipment. Suppliers for a number of users generally stock these parts. Delivery lead times are predictable so replenishment can be managed
• Hardware items (90 percent availability) Nuts, bolts, washers, cotter pins, and other items those are low in unit costs, carried in ample quantity, and readily available from suppliers. These should be stocked in adequate supply in a convenient location so that daily needs can be met.
• Small tools (90 percent availability) Company-owned tools that are controlled by the storeroom tool crib and assigned to craftspeople for use on a specific job then returned to the storeroom.
• General supplies (90 percent availability) All other supplies that includes office and sanitary, operating supplies, chemicals, water, uniforms, gloves, and so on, as well as low value parts (LVP).