We're a relatively small county so we have the luxury of managing this as a senior management team. Rather than have individual DHs make requests of support departments like HR, IT, Finance, etc., we try to prioritize as a team. We have a range of budget exercises we do. We decide on things like major software upgrades, IT infrastructure improvements, etc. If a department tries to "jump the queue" and get IT to address a special project, it gets put on the table. One of the keys to managing support department workload is avoiding the "sneaky" requests coming from individual departments and getting everyone to buy in to group prioritization.