Masturbation

okay,,now we all know that at one point of time we all have had those sexual urges and the best way to deal with them would have been to masturbate. But i guess 1 thing that concerns us all is whether masturbating is good or bad..Amongst teen it's like a big taboo topic but u just can't ignore it. I guess people are confused about masturbating and so am i. so is it really good or bad..coz i know few of my frends who are like addicted to it.and is there some kind of age barrier of masturbation,as in , when we need to stop this habit or wen to start. ??????CONFUSED!!!!