He's been around long enough to see shingles fail that he installed. He's very good. I get the impression from him, that you can't really buy a bad shingle (of well known manufacturers), but the quality of all asphalt shingles has varied over the years, due to certain industry standards.

Additions (like fiberglass) and changes due to current regulations have made some era's of shingles fail fairly quickly. And then every roof is different due to many factors. If you got 30 years out of your last shingles, I suspect the conditions of your house and setting mean you'll get a very good life out of a quality shingle.

Outside of quality workmanship in installation, all the new stuff - 'miracle' sheet underlayments - shingle make up - don't change the general life of the roof. At least, according to him.

If you trust the roofer, I'd trust the shingle the roofer picks.