I started stringing on my real rackets. Unless you do something insanely inappropriate, breaking the racket just isn't going to happen.
But whoever wants to string their own rackets, go for it. I've saved so much money and it's very very easy. After you do it once or twice you'll say to yourself "hmmm, that's exactly the way it should work." You'll occasionally run into something that stumps you for a second...
(like if you run into a shared hole and you can't seem to get the second string to go through... or you forget what the pattern was after you cut the strings off... or you mount it off center... or you weave it incorrectly, instead of over and under you go over and over...or if you're using string from a reel, you miscalculate how much string you'll need, and get to the end only to realize you don't have enough string to tie the knot)
... but seriously it's really no more complicated than changing a tire. For a serious player who plans on playing for the rest of his life, buying a $135 stringer is a no brainer. You can string rackets for your friends for $10 a pop (plus cost of string) and it'll pay for itself in no time, and their hella durable.