If you need something done in Ruby, a gem for it probably exists. Well, a dozen gems for it probably exist. Some of them are elegant, featureful, and well-maintained, and others were written to solve one use case the author ran into that one time. You have lots of gems to choose from, so how do you choose the right one? This choice is important — by the time you regret adding a gem to your project, it’s painful to change back.