Re: Causes of string breakage
1) Spin, especially topspin. Especially if you hit it incredibly heavily.
2) Sheer power coming from the way you swing.
3) Thin, non-durable strings. These usually feel great playability wise.
A more durable string is about the only thing you can do. Talk to whoever strings your racquet and ask them about getting a more durable string since you are playing with spin a lot more now. Topspin makes the strings fray very easily, you probably know what I mean. Some pros use those little string savers you can apply to strings that are close to breaking, because they like the way the frame is hitting. They help, but they aren't anything hugely special.