How do we know when to quit?

A young student recently asked me the following question:

How do I know it is time to quit something and when to persist with it?

Here is how I answered the question:

There is no one answer that fits everyone. There are many ways to figure this out.
 
For me, the best way is to go back to the reason why I started something. If the reason I started something is still relevant and important, I know that I would like to continue to engage on this topic.
 
Then the next question to ask is if the activity is taking you towards the goal or away from the goal. Does this activity give me energy or sap away my energy. If we are even asking this question, at some level we know that the activity is sapping away some of our energy.
 
So, I would go back to the drawing board and do a bit of a brainstorm (I usually try to create either a mind map or a series of bullet point and do it on a notebook or a piece of paper) to figure out what about the activity is not feeling right. Why? Is there something I can do about this so that I get this on track? Am I willing to make it happen?

Explore other ways I could continue to make progress on the main goal. And when I do have options, I explore and see what would add most energy in my life and move me towards my goal.
 
As you can see, this is quite an extensive process. So, I only do this for the most important goals that I am pursuing. For everything else, a simple question helps.
 
Why do I want to quit? Is it because it is difficult and I don’t want to do the work? Or Is it because it is no longer important? And go with the response I get to these.
 
A lot of times, you might just have to trust your instinct and decide based on that.

The student said that he found this answer useful. Hope you find it useful as well.