Is it ture that a person should never give up? Confucious, the greatest Chinese philosopher, commented,"An iron sick can be made into a needle if you have the will to do it." I believe he had it about the right. Generally speaking, a person should persist at his/her goal until it is achieved.
On the one hand, genrally speaking, the statement holds ture. For most people, persisitence helps them overcome difficulties and achieve success.
 Consider politics, Franklin.D.Roosevelt contracted polio at the age of 39. He fought the diseasse with tremendous courage and persisitence and then helped American people regained faith in themselves at the depth of the Great Depression.
 Consider sportsmen, Lance Armstrong was disgnosed with adavanced testicular cancer which hand spread to his lungs and brains. Doctors said that he had no more than 50% precent chance of survival. He had one testicle removed and underwent chemotherapy. One year later, he was declared cancer-free and returned to cycling to win 7 Tour de France championship.
Consider musician, Beethoven nearly lost his hearing in his later life. Despite his deteriorating conditions, he ramained optimistic and composed a series of msterpieces, including the famous Symphony NO.9, completed three year before his death.
Cosider students, I can back up this point with my personal experiences. When I was preparing for the calculus test, I got a bad cold. The practices I had finished seemed had no improvement to my study. I nearly decided to give up if my friends had not encoursaged me. At last, I earned a great score in the test because of the persistence.
One the other hand, exceptions do exist. For instance, when the market is going to fall, selling stocks is the wise thing to do. For instance, when a person is in a bad relationship, probably the wisest thing to do is to break up or get a divorce.
To sum it up, in most cases, we had bettter never give up and the final success will come right after the last try. And in some situations, it is the wise thing to let go.