spares

Spare parts, or spares, are items kept in reserve to replace failed or worn components in equipment or systems. They are essential in maintaining uptime across industries such as manufacturing, automotive, aerospace, electronics, and consumer goods. The term also covers non-part items kept for contingency, such as spare tires, spare keys, or spare reels.

Storage and management: Spares are managed through inventory policies that balance service levels with cost. Key considerations include minimum and maximum stock levels, reorder points, safety stock, lead times, and a bill of materials that identifies each part’s replacements. Practices such as vendor-managed inventory, consignment stock, and on-site spares depots help control capital tied up in unused inventory and reduce downtime when failures occur. Critical spares are parts with long lead times or high failure impact and are often kept in dedicated stock or managed proactively.

Types: Standard spares are routine, readily available items; critical spares meet safety or production-critical needs; obsolescence management addresses parts phased out or replaced by newer designs.

Examples: Bearings, seals, gaskets, filters, switches, circuit boards, hydraulics, fasteners, and tires.

Other uses: In sports such as bowling, a spare is the second shot that knocks down the remaining pins; in vehicles, a spare tire or wheel provides a backup in case of a flat.