Putting "require '[gem name]'" at the top of your Ruby file and running 'gem install' or 'bundle install' can be an easy way to solve a difficult problem. But you could be potentially adding hundreds of lines of code you didn't write or read, for only half a of a fix. Did the gem actually solve your problem or is it just an approximate solution? How much research did you do on that gem first? Are there hidden security risks in it? In this talk, you will learn how to evaluate gems for fit, figure out when it makes more sense to write your own, and how to go about writing your own.