Guitar cables can last up to years, providing you take care of them properly. The main thing is to make sure that they're never bent to the point where there becomes a permanent bend in it, no matter how small. If you can feel little bumps on your cable, that means your cable's been bent too many times. Remember that there are sensitive wires in it, so keep good care of your cable, it can really affect your tone. Also, the shorter the cable the better, so get it as short as possible (but still allow enough cable so that you roam around a bit).

I've never heard of anyone getting a patch cable fixed... they only cost around $20 or so it's probably not worth it.