I have replaced my N900 exactly a year ago since its eMMC stopped working. This was my second N900 with the same problem, the first one still works using MicroSD as part of the system (the phone also has a 256 MB primary storage which still works).

The second one still could be waken up the same way, however, it also had other problems like loosing SIM connection sometimes.
I had two main problems at last - slow CPU and few RAM, the latter is only 256MB altogether.
It was not really able to cope with modern web pages.

However, I remember a few years ago we were presenting a new system which were still under development running at a private computer somewhere else. The computer was connected to a UPS, but it did not work and a power outage restarted the whole system two times during the presentation. Fortunately, I could use my N900 to get everything to work again not leaving us in trouble. Today's phones without a landscape querty keyboard are completely unusable in such situations.