I purchased several books here in Barcelona. A few editions of Lorca and Lezama Lima, some contemporary novels, some new books of poetry, some political articles. The two teaching assistants on my program were great, saving my ass many times over. One thing I noticed, though, was that they didn't buy books or browse in bookstores. They are specialists in earlier periods of Spanish literature, and Quevedo is not publishing any new novels any more. (It could be a money thing too, but I still bought books when I was their age (29-30) and equivalent level of grad student poverty.) Still, I think I would buy almost as many books if I were a medievalist. For me, maintaining a personal library of books is inherent to my identity as a scholar and researcher. (Sure, there's the library, but it's not the same thing.)
This gives me some insight into my own assumptions. I have to stop assuming that other people resemble me, even though they "should" if they want to be like me. But should they want to be like me? In a word, no.
So my advice is geared to people who want to be like me, in general terms. To assume the same level of drive or intellectual curiosity / independence in other people is a big mistake on my part.