Maintence costs are also significant. One way to estimate these types of costs is to develop a plan that at least covers the routine or planned maintence. For example, at Dartmouth, we have a plan that estimates costs: assuming that projectors need replacement every four years, that classroom computers need replacement every two years, and that the other componentry will need replacement every eight years. With such a plan in hand, we know, or at least have a fair idea, of what our plan maintence costs will be five and six years out. On top of that, you need to plan for unplanned maintence, equipment that fails, backups so you can swap equipment in and out, and things like that. On top of that, might be the physical aspects of the classroom, such as carpeting, chairs, window darkenings, etc. Bottom line is that these maintence costs are significant and they need to be taken into consideration in your planning. One suggestion easier to say than to do: don't defer maintence with respect to your classrooms.