I've always operated by the tenet that, if they take my money, I am justified in staying for as for long as is necessary. This seems to be the generally accepted precedent, as I've seen an immeasurable number of people purchase a single item and spend an entire day working. This is especially true of local, boutique coffee shops, at which the patrons seem to be less transient than those of, say, a Starbucks. Personally, I generally purchase a single espresso for $1.50, add milk to attempt to simulate the taste of an actual cappuccino (at one third of the cost), and stay for between three and six hours. This seems to be standard operating procedure for many people. Are extended stays stigmatized elsewhere?