I replaced my starter contacts ~ 8 months ago ~15,000 miles. They seem to be heading south again, whenever it gets below 20F the starter kicks a few seconds after the key is turned. My wife always drives the car, and never turns off the headlights - anyone speculate that having the lights on during starting kills the contacts sooner? Anything else that could cause them to die this soon?

I would check your main battery cable to the starter for a problem. Also make sure your battery is good by having a load test done.