I wonder how often oil needs to be changed. My Lexus rx350 is every 10,000 miles with synthetic oil. I can't imagine every 3000 on Tahoe
Per the manual, oil should be changed every 5,000 miles. The Dexos 1 oil specified by GM is a synthetic blend oil 0w-20. I'm changing the oil early the first time because I'm anal and believe in an early first change to clear out any leftover assembly lube and initial wear-in particles. Not required by GM, and some say unnecessary due to today's engines being assembled more cleanly than in years past, but something I've done on all my new cars.
I also plan on switching to full synthetic oil (Mobil 1) and going about 10k in between changes. Yes, I know the onboard computer won't agree with this, but I'll make it
Oh, and no cheap oil filters either.... I'll pay the extra couple of bucks and use GM filters.