It's now 101 days since my last booting the laptop. It may be not surprising for a server to run continuously for several hundred days, but it is rare for a workstation. Windows users have the habit of shutting down the computer when they finish working with it and reboot it again the next time. Even though Windows 95 or 98 had the capability of hibernating, saving the running state to hard disk and resuming late, that method was rarely used, even with laptop users. No sure how many Windows XP or Vista users would keep hibernating their computers.
I'm a Debian GNU/Linux user and find it annoying to have to reboot the computer. The save-to-disk feature is great. Besides saving a few seconds rebooting, it also means I can resume work at wherever I stop last time. I don't have to relaunch some applications, reopen some files, and so on.
I've used the save-to-disk feature for quite some time. Except upgrading to new kernel versions, I don't have to reboot. On rare cases running Stell Bank Common Lisp may lead to memory swap that forced me unplug the power and thus reboot, but that's my own fault: my Common Lisp programs were not frugal with memory (trying to solve Project Euler problems) and my laptop was endowed with just 1 GB memory.
Keeping a desktop system running for so long does pose a grave test to the OS and the applications. For instance, I sometimes have to exit from GNU Emacs so that the system can hibernate successfully. After about three months running, I also noticed a bit performance hit when resuming. It takes more time switching applications after resuming than before. Konqueror and Kontact, in particular, will consume a lot of memory after running for so long. I guess 2 GB memory will eliminate the annoyance to a large extent. The delay is generally tolerable. If not, I can always exit and relaunch the specific application.