To my dismay, LBS informed me that you have to replace the whole rim when it wears out. Even if you have a carbon rim with an aluminum braking surface. The guy went into he back for a moment, and came back with an Edge rim with a bunch of spokes dangling, with no hub. Its owner had worn it down racing cyclocross.

Suppose a person were to use a carbon wheel set as every day wheels, except in the rain. But also suppose that person lived in a place with gloomy winters, where it can be cloudy for weeks at a time, and he prefers his road bike. There will be days when it's dry and calm when I leave the house, but get caught in the rain before I get home. I'm also taller and heavier than the average roadie, and do a lot of hill and mountain riding.

Any guess how long a set of carbon rims would last me? Or, at least, how their longevity would compare to the metal ones I've got now?