Back in January, Sandi Metz introduced her rules for developers in a Ruby Rogues podcast episode episode. Around the time Sandi’s rules were published, the team I am on was starting a new project. This post details the experience of that team applying Sandi’s rules to the new application. The rules _There are four rules._ Here are the rules: Classes can be no longer than one hundred lines of code.
![Sandi Metz' Rules For Developers](https://cdn-ak-scissors.b.st-hatena.com/image/square/196e5c4690130eea516f4142c936aa1ec3eeb288/height=288;version=1;width=512/https%3A%2F%2Fimages.prismic.io%2Fthoughtbot-website%2FZn0Q2JbWFbowe7qY_default-article-background.png%3Fauto%3Dformat%252Ccompress%26mark-x%3D356%26mark-y%3D100%26mark64%3DaHR0cHM6Ly9hc3NldHMuaW1naXgubmV0L350ZXh0Lz90eHQtbGVhZD0wJnR4dC10cmFjaz0wJnR4dDY0PVUyRnVaR2tnVFdWMGVpY2dVblZzWlhNZ1JtOXlJRVJsZG1Wc2IzQmxjbk0lM0QmdHh0Y2xyPWY1ZjVmNSZ0eHRmb250PUlCTVBsZXhTYW5zSlAtU2VtaUJvbGQmdHh0cGFkPTAmdHh0c2l6ZT02NCZ3PTgwMA%253D%253D%26txt-align%3Dcenter%252Cmiddle%26txt-color%3Df5f5f5%26txt-fit%3Dmax%26txt-font%3DIBMPlexSansJP-SemiBold%26txt-size%3D24%26txt-x%3D391%26txt-y%3D526%26txt%3DCaleb%2BHearth)