I've been commuting (and doing group rides and some training) on my 1992 Trek 1420 7-speed road bike for the past 4 years. I always carry a rear pannier and in the last year or so started pulling my kid to daycare in a trailer. The bike has the original wheels but I've recently started breaking spokes in the rear - 3 in as many months. The wheels are 32-hole Matrix ISO CII laced 3x to 105 hubs. Other than the spoke breakage, the rim appears to be ok (brake track isn't scooped, no cracks) but there does seem to be a pattern of more brake wear at the spoke holes.

I've taken the rear wheel apart and plan to either rebuild it with the existing rim and new spokes/nipples or use a new rim. Many of the nipples were getting very sticky and some were rounded off so I figured it was at least time for new spokes either way.

Since this is primarily a commuter bike, I don't like to spend a lot of money on it. My goal is to maximize the miles/$ investment. For that reason, I'm having a hard time justifying the purchase of a new rim. It's been recommended to me by a riding buddy that I should get a Velocity Deep V but I'm not completely certain I need a new rim.

What are your thoughts on the matter? Should the Matrix ISO CII rim stand up to a few more years of commuting duty if I rebuild it or should I drop coin on a new rim?