My 2001 5.3 burned oil for about the first 15,000 miles, then it burned none until about 50,000. It now burns some oil, but it depends on the brand and weight. I get my oil on sale or with rebates, so it is very seldom that I run the same oil twice in a row. The most the engine ever burned was a little more than a quart in 5200 miles. That was my last oil change. I think it was 4 year old (Oct 2006) Quaker State 5W-30 Synthetic.