Considering how cheap, and how important, the carb is, a spare one is a good idea. You may have problems with the casting itself ?
I put a new carb on a Honda lawnmower, ran good, than died out, wouldn't start. I drained the fuel bowl and got about a Pepper
Packet full of black grit in Gas. I checked the fuel, nice and clean. realized the grit came from the carb itself, as the problem never re-occurred.