Not selling any of mine. Most shoot too darned good to give up/sell.
Parts? One of them may break, one of these days. I have never made an order out just for what I needed. Shipping costs are the same whether I bought some CGW lower powered trigger return springs, firing pin block springs, etc. or all that plus various assorted spring, pins, screws, a hammer here and there, a barrel bushing, etc. Every time I get what I ordered I also have small bags of other parts to squirrel away in the divider boxes in the shed.
Like reloading supplies. Don't wait till you need them. Buy them when you see a good price on something you know you can use. Parts, primers, bullets, powder won't go bad in my lifetime.