"RENT" is based on Puccini's opera "La Boheme", and the modernizations are pretty accurate. If you do some reading on the opera and the play it is based on, then I'm sure you will find the answer. I'm thinking that Rodolfo (Roger) and Marcello (Mark) became friends because they had a lot in common, living in poverty-stricken conditions and trying to make names for themselves as artists. They seem to have known each other a long time, judging by how close they seem. ) Other than that, I don't know if their is any clue as to how long they have been friends. I just recently saw the film version of RENT for the first time, and I haven't seen the opera, I only own the CD. I hope I helped.
In the movie and/or broadway show RENT, is it ever said (or sang) how Mark Cohen and Roger Davis met? Or does it give any indication about how long they'd been friends?