Hi, it is an expression usually used with the meaning of: do not consider everything happens in your life as something that is granted, sure or even due for some reason or event" The obvious consequence is that you should apply yourself in doing something bye :)

This phrase generally means: take to be the case or to be true; accept without verification or proof take sth for granted means: not to appreciate or not to realize how much something means to you. - Don't take your life for granted; it is so precious. - I don't take my life for granted at the moment because of some positive changes. - I seldom take others' lives for granted except out of basic unconsciousness.

take for granted 1. To consider as true, real, or forthcoming; anticipate correctly. 2. To underestimate the value of: a publisher who took the editors for granted. http://www.thefreedictionary.com/take+for+granted This is an excellent resource for many of the words you wish to know.