Why establish a formal evaluation criterion when considering the purchase of hardware for the organization?

== == Software often cannot communicate well since the machines are of various ages along with their software. Get rid of this problem by focusing on one brand and keep in a timeframe when updating this software. Such as Windows for example. They are always updating to repair a messup or updating to finish an update. No software or hardware should be used more that 3 years before the replacement cycle begins again. This ensures that all of the machines can communicate at the same level and that all of them have the same protection packages. Why is it recommended to establish a formal evaluation criterion when considering the purchase of hardware for the organization?