It's also useful to profile your compile times. Sometimes the compiler is spending most of its time on some small sections of code.

For instance, I was working on a project where the use of one library constituted 80% of our compile time! The library allows you to declare autolayout constraints using operator overloads (i.e. `foo.top == container.top - 20`) and apparently the amount of type inference was just murdering our compile times. Changing libraries took this project from being awful to work on to quite pleasant.