How often do you reboot?
When terribly busy I simply quit restarting my Macintosh — for weeks — and by busy I mean heavy work in lots of applications both at the office, in presentations and at home.
Today is the 14th day from the last reboot and I guess it'll have to march on some more (in the days of Mac OS 9 something like this would've been a miracle), but it will eventually become sluggish and I'll restart it instead of isolating and killing the processes that hog the system resources or leak memory. I know the uptime-victims that would prefer crucifixion to a reboot (not talking about sysadmins here, those guys get nailed for bad uptime records), and I am definitely not one of those: I usually don't even care.
How often do you shut down / reboot the computer you're working on? Do you simply ignore this and go on for weeks? Hours?