Let’s compare the costs of an in-house Exchange solution for a 10-person company with the costs of a hosted Exchange solution. We assume the company will keep the solution for five years before considering an upgrade. We also assume the company has 3 users who require mobile connectivity, 2 BlackBerry devices and 1 Windows Mobile.

This chart clearly demonstrates the upfront and ongoing cost advantages of a hosted Exchange solution, another economic point to consider is that most in-house software purchases are based on hopeful predictions of future needs.
In other words, a company spends more now to be able to accommodate growth down the road. On top of that there is the upgrade factor, which means having to buy, test and deploy new versions along the way.