It's going to depend which brand of module you buy, does it work as advertised or is it an overpriced piece of crap that just dumps in more fuel, no sensors or safety limits.
It's also going to depend on how and when and how often you make use of that added performance. Someone on another thread said they'd seen chipped vehicles run for over 100K miles with no problems, and other blow apart in less than 10K miles. Of all the components on the vehicle, a lot of it comes down to the loose nut holding the steering wheel!
Don't just jump on the first module that strikes your fancy, talk to people that have used them long term, do some research to see what features they offer, and pay attention to their advertising - are they just screaming about gut-ripping power, or do they seriously discuss the engineering behind the product and give you some honest-to-god data to look at?
Also, what are you looking for? Are you a flat-out speed junkie that just wants to hot-rod your vehicle, or are you looking for a potential MPG increase when driven normally, occasionally calling on that added power for towing, steep hills, or merging onto the interstate?
If you're concerned about reliability and not damaging your vehicle, look for something along the line of a Banks Six Gun tuner, that monitors most if not all of the OEM sensors on the engine and tranny, that has built in safety limits, and where they make a point of discussing how these safeties are set up to prevent damage to your vehicle.
