For me, I was thinking of Gene Wolfe when I wrote that. I've reread the entire "solar cycle" at least once every couple years for the last 20 years, and of course I own all the secondary material I can find on it. And I subscribe to three different podcasts where people just discuss it. And Youtube channels, and mailing lists... I don't think I'll ever really get to the bottom.

But it's not uncommon for people to do this with religious texts, too. Reading for devotion, for understanding, out of a since of obligation, whatever. Doesn't matter: it's a distinct way of interacting with books, different from reading a potboiler mystery novel.