Housing off campus is easy to find, with plenty of affordable places close to campus. The biggest attraction is that the prices per month, especially split between housemates, can be an extremely good deal. With the compactness of the campus at UR though, and the sense of community, many undergrads find it best and most convenient to live all four years on campus rather than off. Even Take Five students in the fifth year of their studies will live on campus. Groups tend to move into suites and are content to be in the dorms if it means they are able to live conveniently with friends. People do move into houses in groups, though, if the suite option isn't the most palatable.
The University does not own any off-campus housing, so if you decide to move off campus, you're on your own. If you have a car, it is workable to live off campus, and it will save you money by not paying room and board to the college. For more independent spirits or people with off-campus jobs, it may also make sense to not live in campus housing. Still, students often choose to live on campus, especially in Hill Court or GLC, where you feel somewhat off campus but are still technically in dorms. For certain circumstances and upperclassmen, off-campus housing is the right option, but it is not a choice made by the majority.