Man, I've had it with Pontiac corroded battery cables! With my 97SE Bonneville, I went through replacing the alternator, then the battery, and finally the battery cables, which had corroded inside the insulating jacket, where you can't see it. (Left me stranded several times.) Then we went through the same thing with my wife'* 88 Grand Prix; alternator, then battery, still had problems, turned out to be corroded battery cables, after she got stranded a few times. Then she got a 2001 Grand Prix GT. Just today she got stranded. I just zeroed straight to the battery and the cables. There were wads of corrosion all over the positive terminal and the cable connector and battery hold down bolt had partially corroded away. I got her a new battery, then sent the thing to the dealer to get new battery cables. They called me later and told me the negative cable is fine, but the positive was completely corroded. It seems like it'* always the positive cable that corrodes away.

It also makes your headlights dim when you're idling at night. Her car is only 3 years old!! Maybe this happens with all cars, but man, 3 years isn't a lot of life for a battery cable! So check those things out, and don't just trust the external appearance! Unscrew the positive cable battery terminal and make sure it'* all clean and shiny!

Also dress the cable with some dielectric grease to keep out moisture and prevent corrossion.

don't buy Delco batteries, I've changed waaaaay too many GM cars that had Delco batteries with faulty terminals

Word up on the Delco battery. Over the years I've tried many different brands, including brands from Autozone, Delco, Interstate, Exide, NAPA, etc., and so far the only brand that hasn't given me any trouble is the Sears Die Hard Gold series.

And props on the suggestion to put some dielectric grease on that positive terminal!

I'd say that in addition, maybe a twice-a-year general inspection of the battery exterior, up to and including removing the battery and washing out the battery tray and rinsing off the exterior of the battery to keep it all clean is probably good preventative maintenance. And squirt some oil on the battery hold-down clamp bolt. I don't know why it corrodes so extensively, but I've seen that thing caked with corrosion and have it errode away, or worse, chemically weld itself to the battery tray so the bolt head just twists off when you try to pull the battery. -UGH!