Yes, I would keep a spare on hand. But I am guy who has spares for everything. Nothing I hate worse than to be out of commission for lack of $3 part. How long do vents last? I just replaced on in my 50cal. The vent had been in since 2002 and I have no idea how many shots were out through it. But it had wore out to just over .090 and I thought I was seeing accuracy go away, so I changed it, from parts in my "spares" bin.