Is it true that when i start taking statin i should take it for life?

Depends on how much: You can control your LDL cholesterol with diet and exercise. Oftentimes, LDL chol level is genetically determined and not affected by life style changes. If this is the case, answer is yes. If not, you can taper and even stop when your LDL chol is back to normal levels. This is for primary risk reduction. If you already had a cv event such as stroke or heart attack, again yes.