Rvm allows users to deploy each project with its own completely self-contained and dedicated environment - from the specific version of ruby all the way down to the precise set of required gems to run the application.

having a precise set of gems also avoids the issue of version conflicts between projects, causing difficult-to-trace errors and hours of hair loss. with rvm, no other gems than those required are installed. this makes working with multiple complex applications where each has a long list of gem dependencies efficient.

rvm allows one to easily test gem upgrades by switching to a new clean set of gems to test with while leaving the original set intact. it is flexible enough to even have a set of gems per environment or development branch--or even individual developer's taste!