When should you resign from your job?

I
have read many article of when you should resign from your job. Most of them are explaining about reason because not happy of working place and working atmosphere. One of my friend said that there are 4 reason to resign: salary is too small, no more challenge, career and dedication to working place. It might be true. But I have different opinion. Salary too small.. mmm I still can consider, since there is no exact amount of enough salary... no more challenge... might be also. Ah.. I think 4 of them can became a reason to resign. I think I will add 4 more reasons, which for me more important.
1. Because of health, since health can not be bought by money
2. Family need you, since family is also can not be bought by money
3. Your boss have ever think to find another one, since there is no guarantee that next time they will not do it. Even there is also a possibility that it is only because want to know your being. But for me, I will give things that I possible to give to company, as long as they need. But happiness is important. If the company think more happy without you in the company, although many way have done to it. It will make a question mark.
4. Pride, since it is also can not be bought by money.

So, regardless my friend opinion, I more consider to a priceless things. Sometimes, even an employee have give a dedication... but it can be not enough. Never been enough. Do you happy working in your work place? Do company want you? The answers is in your heart. Life must go on.