The power of Ruby comes from a huge number of available gems. "Just use gem X" is often an answer presented in blog posts or Stack Overflow topics. However, each new gem has an impact on the future maintenance cost of your application. Some gems are optimized for a short term perspective - they give you an instant burst of productivity, but you have to pay for it later on. Other gems require more initial effort on your side, but they are much more flexible when you have to introduce some non-standard changes. In this talk I will show you how to select gems for a long term perspective - as if you were to support your application for the next 5 years.