There's little reason for this to be the case anymore, given such things as Bundler [0] and RVM [1]. The former lets you define, per project, the exact version

There's little reason for this to be the case anymore, given such things as Bundler [0] and RVM [1]. The former lets you define, per project, the exact version of the gem to use. As Rubygems.org hosts all old version in perpetuity, you should never be forced to use a newer version than you have tested. RVM, meanwhile, has the concept of gemsets, which are completely independent sets of gems which can also be used per-project, which solves the problem of two programs needing different gem versions. [0] http://gembundler.com/ http://gembundler.com/ [1] http://beginrescueend.com/gemsets/basics/ http://beginrescueend.com/gemsets/basics/