The key isn’t whether or not you quit an effort, it’s why. Are you quitting because you’re tired and just don’t want to make the effort, or are you quitting because you have learned something that has re-framed the problem you’re trying to solve?

The first issue is one of motivation or clarity of action at the least, and possibly also one of character.

However, the second one is the honorable kind of quitting. It means that you’ve recognized that your efforts – no matter how focused and valiant – will [practically speaking -mfn] never result in success, and could probably be better spent elsewhere. In this situation, the reason people don’t quit is typically due to pride or insecurity, both of which will potentially lead to wasted years and energy.