azalea wrote on Jul 20^th, 2010 at 11:28am:

Quote: One spare for 2 canoes?  That sounds like saying, "I have seat belts in my other car, so I'm covered." A paddle is similar to many other "vital" items we take on trips: orienting devices, stoves, flashlights, paddles, canoes, tents.  We assess the liklihood and severity of failure, the weight, etc; and make a decision of how many (if any) backups to bring.

Spot-on accurate statement, as I see it.  We bring one spare paddle per trip regardless of how many canoes we have.  In 25 years of tripping, we've never broken a paddle, thereby making it a slim chance that even ONE paddle will break on a trip, let alone more than one.  Thus, the reason we carry only one paddle as insurance.

As Azalea said, one assesses "the liklihood and severity of failure" and makes a decision.  Based on past experience, one paddle per group is more than enough for us.