I was able to pass a Vista MCP exam ago some years ago without any preparation. But then I have years of experience and I would expect that most MCP exams in my area I could pass without any study. What I find is that often people who have experience without any formal training have gaps in their knowledge and end up expending a lot of administrative effort to do things that should be relatively simple. Or avoid tools, like Group Policy and PowerShell, because they can be difficult to understand if you haven’t studied them in detail. I agree that certs are not a necessity once you’ve got the core concepts down and have experience to go with it. But I think they can be valuable at the start of your career and make life easier on the job.