Too Long; Didn't Read
People keep saying that a one line source code change should take one second to be “effective”. “<a href="https://hackernoon.com/tagged/effective" target="_blank">Effective</a>” meaning that you get some form of feedback — at the very least first error messages if you screwed up, or ideally that changed line is already running within that one second and you can observe what you told it to do (as opposed to what you wanted it to do).