Quitting is negatively viewed in our productive culture. We think that there is something wrong with the player. That they don’t have what it takes. But quitting is an important skill. It takes evaluation and seeing the landscape as is. When we are quitting, we are taking power, not giving it away.
You should quit before starting a project that you don’t feel you can commit to the end.
You should quit when your assumptions were wrong and now that you are here, you can see more clearly something isn’t going to work when you thought it could. That is accepting the risk that sometimes things don’t work out.
You should quit when you are out of resources. Time and money are not unlimited. You can be using that on something else. Sunk costs are also real. It is difficult to quit mid-way through med-school when you realize you don’t like blood but it is better than committing to a career you are not passionate about.
There are plenty of good reasons to quit. Just make sure you are doing it for the right reasons. Keep your head up because now that you have quit this project you can start your next one.