Knowing When To Stop

   This subject that I am writing about might be one of the hardest things to write about, but it is one of the most honest from the heart things to write about. Loving an activity is a good thing for many, being a stress reliever and relaxing thing that gets them away from the real world. But when other factors come into play such as family, health, etc. is there a reaching point to just stop.
   I understand people having passion for what they are doing in life, but when is enough truly enough. A good example is my friend I run with, his knees are about to be gone basically killing him everyday at the age of 21. What does he have forward to look in life if he keeps running his body is going to be destroyed from all the running. The doctor has even told him that if he keeps this routine up he won't be able to get down with his kids and play with them on the carpet when he gets older.
   Personally, I feel that you can't let moments like that go away in one's lifetime. Your children aren't always going to be young, you had your time with running and it was amazing, maybe its time to shut it down? That's easy to say on my point of view because I am not in that situation, but it is something that I feel should honestly be thought about. My friend is really bold headed when it comes to something he loves and doesn't think about the consequences all the time. I love him for who he is especially with his determination to do what he loves, but the question for him to ask himself; Is it really worth it when it is all said and done?