I'm lucky to have a server in production for three years that hasn't been rebuilt and re-purposed
Advancements in hardware mean we do regular upgrades and hardware refreshes on our infrastructure.
I once had a router that had about 7 years uptime on it (admittedly, we did just leave it on and in a rack hooked up to the network dealing with a trickle of dialup traffic for kicks... sad I know)
Cursory glance through our infrastructure at the minute and it looks like the longest individual box uptime
14:06:16 up 423 days, 48 min, 0 users, load average: 0.13, 0.12, 0.09