Planet Waves tends to make decent quality cables, so I wonder if it's something that you're doing.
How is your bass's jack set up? are you using a straight plug on your cable, when you might be better served by a 90 degree plug? It's common for players to rest their bass on their leg without them ever realizing it, and that will sometimes hit your plug and mess it up over time. A 90 degree plug can fix it fast. For example:

Good

Sorta bad. This kid will probably screw up his cord and/or jack pretty soon if he's not careful.

Bad. That cord is primed to get messed up, as is his jack.
A slanted guitar jack on the face of the guitar should use a straight plug:

Good.
As a rule of thumb, you should always run your guitar cable through your strap so you mess it up less when you step on it accidently, and unless you have a Strat-style jack on the face of your guitar, you probably want a 90 degree jack, as they reduce the chances of you messing up the cable and the jack a whole lot.
Also, how are you storing your cables? Are you wrapping them properly when you put them away? If you're not sure, then you probably are, and that's an excellent and almost surefire way to destroy your cables.
If you're not familiar with it, find out how to wrap cables using the "over/under" method. That way, you're not twisting your cables at all while putting them away, and they'll last forever.
Other then that, yes, there are cheap ones out there. You get what you pay for, and the cheap ones will break quickly. I always get coaxial to reduce noise from other electronic stuff (power supplies are the worst, usually). Monster Cables are really good quality, but you'll pay for it (especially with the higher end stuff). I also buy alot of Rapco ones because they're on cheaper side, but I keep good care of them and they're very easy to fix with a soldering gun. Between the two, they last forever, also.
Don't worry about the 'gold-plated' crap and the sonic qualities of certain expensive materials over others. It might be testable in the lab or with equipment, but no mortal will ever hear the difference. That junk is just designed to get more money to part with you.
Bottom line is that if the cable feels solidly built, then it probably is. Take care and properly store your cables, and they'll last a long time. Also, make sure that you have the right plug for your instrument and that you're not unknowingly putting strain on it while playing normally with your instrument.