In Turkey, where I live, almost all universities restrict access to staff and students (only their own students if not a graduate student); the only exception I can find is the Koç University where paid membership is open to public. I've researched in the past and found that major universities around the world---i.e. Italy, France, UK, US; selection factor being the languages I can read---seem to allow the public to access in one way or another (article, in Turkish, with results). But I wonder how accurate my reading is with the reality, and thus I'm asking this question.

So, as a plain citizen w/o any current affiliation to any educational institutions, can you access university libraries where you live? Does it matter if you have certain diplomas or affiliations? How easy it is?