1998 lumina with 70,000 miles.i bought it with 40,000 miles from original owner. noticed the alternator had been replaced at least once. my local friendly auto electric shop guy tells me he up the quality of the alternator by installing some heavier parts i believe. i live in hurricane katrinaland and need this car for evacuation purposes . stuck in stop and go in traffic 10 hours for a 90 mile trip last year. do you guys recommend servicing the alternator now or just keep my fingers crossed and buying a lifepreserver?