You're correct Ray, I was thinking you were talking about a computer running 24/7 like a server. When you plug a card into the computer it's still receiving power, although not as much as it's actively transmitting data.
Think of it this way - Using a modem on occasion without stressing it is like driving a car 10K a year. Using the card in a router is like driving your car 15-20K a year. In either scenario if you're running it hard, IE - downloading a lot you'll notice your modem start to get really hot.
Heat is always an enemy of electronics and the more you use it the quicker you'll wear it out. I've used cards 24/7 in routers transmitting roughly 15-25GB/mo (grandfathered accounts) and ended up replacing devices slightly after 2 years. Most people won't transmit that amount of data so they'll see a longer lifespan, but to be honest it's the luck of the draw. I've had people that have had cards going 4+ years without issues, while others fail much sooner. That's the downside to electronics, you can never say exactly how long it will last.
Sorry to hear that Jim, keep in mind the UML290 is bleeding edge technology. When you live on the cutting edge you're basically like a paying beta customer. I'm really hoping that Verizon works out some of the kinks with their 4G wireless network to make things as reliable as existing 3G devices. The good news is you'll have a warranty till at least Dec 2011, which means you should be able to replacements till then without issue. They're getting closer, I'm hoping within the next few months they get everything fixed and it just works like 3G cards do now.
