Regular pieces. It refers to parts that are often used, such as high frequency, large loss of equipment and cheap univalent, such as vulnerable parts, large consumption parts, and key equipment, and so on.
(2) very spare parts. Parts with low frequency, small stop loss and expensive unit price can be divided into plan purchase parts: purchase parts in advance for short-term reserves according to repair plan, purchase items at any time before repair, or parts that are used immediately after manufacture.