Longest run without restarting

Here is a somehow silly question: what is the longest run without restarting for Plone installation you've seen?

This is just for anecdotal purposes. I commented with a colleague about a Plone installation running for two years straight without any intervention, but I guess some of you with more experience than me might have some more impressive examples.

there is a long discussion on the need (or not) of restarting. you might find it interresting