Wear and tear is generally not an issue with network equipment. You buy it, you run it until it depreciates or breaks or becomes too much trouble, you replace it. I've never heard an argument of "don't run that thing too hard, it'll shorten its life". (If you do hear this, it's usually a sign of inadequate cooling).

Data caps are a poor tool for handling congestion. They're a great tool for frightening people into keeping their load low(and costs for the provider down), or for sucking more money out of people. They don't do a damn thing for immediate load.

Me? I have Comcast business class -- they guarantee me a specific bit rate and I can nail it up at that rate all month long and they don't care. For folks not paying for this service class, Comcast has bandwidth reservation and all the anti-congestion tools they need, they just don't use them -- they get more money out of people's behavior towards data caps.