Cem Kaner, co-author of Testing Computer Software, has suggested that test plans are written for two very different purposes. Sometimes the test plan is a product; sometimes it's a tool. It's too easy, but also too expensive, to confuse these goals.
In other words, a test plan is like a power tool. You should not utilize them if you don't know what you're doing with them. You are wasting both time and money.
