Extra Propeller?

[imyourhuckleberry]

Anyone else have an extra propeller sitting with their marina in case they hit a rock?
I was told its a good idea for a couple reasons; It can really mess up your engine + boat to drive around with a damaged prop, and you'll lose valuable time on the water during the season waiting for the part to arrive from the manufacturer.

I haven't heard of this, but it makes sense to me. Is this something boat owners invest in?