Having spare parts available just makes sense to me. Experience and my nature compels me to be prepared for occasional failures. Parts like ejectors, springs and sears can wear or fail over time or even sometimes when new. Considering my M97 is 80 years old now I'd be more inclined to have possible spares. Just as an example the first time I took an original, excellent condition Inland M1icon Carbine to the range the sear broke.