When you work up a project plan that requires some network staff effort, do you take into consideration that they are not really available a full 8 hours a day? I have only worked at some places that did proper resourcing in their project management system, whatever application they used. Some project management apps will allow you to take actual calendars into account. I have provided calculations we have used at ACME to determine how much time our network staff really have available for projects and support.
In general here is what I have seen from my experience, how much time on average your network staff have available for projects and also suppport operations. First you need to take the full hours that any staff member has at max available per year, 2080hrs (40hrs/week x 52 weeks). Then you take out vacation time, training time, holidays that fall on a work day, corporate admin requirements, and department admin requirements. Estimates I have used include 2 to 3 weeks of vacation, 2 to 3 weeks of training, about 8 holidays that fall on workdays each year, 4 hours a month of corporate admin time, and 3 hours a week of department admin time. This leaves you with 1620 hours available for the year. You have just about lost 25% of time available from your network staff (or any IT staffer really).
That 1620 hours for network staff has to include project work and support operations as well. Historically, and based on the above, I have witnessed that network engineers for instance have about 40% of their overall time available for project management. They spend about 35% of their time on support for systems, operations, maintenance, level 2-3 helpdesk and so forth. So at 40% that means they have about 875 hours for project work. Not nearly as much as 2080 eh? Good project management dictates that we should factor this into any planning for new systems being implemented. This also can help when you are trying to justify a new network person on your team; you can show that to achieve the projects planned for next year you need another person (or more). It can also help with contracted resource justification, getting a network temp worker.