I did buy a ticket for four visits to Le Vie dei Tesori places, and then picked four places that I came across in the centre. It was a bit of hit-and-miss. One was quite interesting, one a bit less, one was in theory interesting but not so much in practice, and one was downright boring. Won't name and shame, though. And of course, if I knew Italian, I would have learned more from the guided tours. (In one place the guide did do it in both Italian and English.)