We have our general network budget that we use for upgrades and equipment refresh, as well as tools and other network related projects. Most often though, our tasks are funded through outside project budgets and service initiatives. The most mind boggling thing to me is that, we use a hot potato method on non-project purchases. If a data closet needs a patch panel / switch, whomever makes the request for additional capacity usually foots the bill. So if a project needs 3 switchports, and there are only 2 available, they either make do (most often) or they buy an entire new switch (less often).
Some departments try to re-purpose things, hoping that they can make it work until IT pays for it to be refreshed... but that gets denied most of the time.
