Poor you. My first N900, obtained in June 2012, is still going strong. With the original battery. Lasts about a day if I use it, about a week when offline. I bought it second hand, so it is much older than that.

Of all five N900s that passed through my hands, four had no problems. One had a loose display due to the previous owner not treating it very well. None had any problems with the modem or the USB port, but I strengthened the ports anyway just in case.

It is true though that some of my other devices are older than that and still going just as strong. None of them are Nokia, BTW