When you buy IT from anybody, the basic assumption is that it will be obsolete within 18 months, sometimes even before you install it. As soon as you buy something, you have to figure out how to get off of it. This is the barrier to exit. If you're not moving forward, you won't be able to take advantage of all the security features you need, and the barrier to exit dwarfs the cost of buying and installing the equipment in the first place. Scott McNealy