An outside observer might imagine that just about every IT department would have some kind of technology road map. After all, without one, how could you avoid costly mistakes such as overspecifying or underspecifying new infrastructure hardware purchases? But all too often that documentation simply doesn't exist for one very simple reason: How can you possibly build a coherent technology plan in the face of immediate and constant change?
The trouble is that a plan that includes the additions and modifications to your infrastructure you'll make over the next three to five years often takes so long to do correctly that it's completely outdated when you're done. That alone is enough to cause many IT departments to simply give up and resign themselves to a life of reacting solely to immediate needs -- a stressful existence invariably resulting in blown budgets and orphaned hardware that was outgrown far too early in its lifecycle.
It doesn't need to be this way. You can plan for the future in the face of rapid change without all of your work being for naught. Here's an eight-step process for such a task; I've found it works well.
First, define the period of time your technology road map will cover. This varies based on several factors, including how often your organization adopts new technologies and what your long-term budgeting requirements are (or should be).