If you don't setup for a enterprise scale install, you'd probably be better off with a more lightweight alternatives.
has a reputation for being "an enhanced wiki and issue tracking system for software development projects. Trac uses a minimalistic approach to web-based software project management." But you can do general support tasks with it as well. "Reduce to the max." ;-)
I studied it up from the ground for at least half a year before attempting my first production deployment. While this might be no strict pre-requisite, you might need to become an expert in every system you want to deploy with long-term-support, right?
Disclosure: I'm an addicted Trac plugin developer and application maintainer for several Trac applications with a few dozen concurrent users per application. As soon as there's some useful data people tend to understand the concept of the ticket and wiki system quickly and will love it for it's power and simplicity. I train staff of all ages, and had very little adoption problems so far.