So your plan is to buy a new machine as a result of a software issue, a network issue, or another problem that has nothing to do with the hardware like a corrup

So your plan is to buy a new machine as a result of a software issue, a network issue, or another problem that has nothing to do with the hardware like a corrupted image? When you have 100 machines, you can probably afford to do this. It would be silly, because when you only have 100 machines, most of your problems will be software or network issues. Still, you can do it and it probably won't cost you a kidney. When you have ten thousand, you can't. And this is even assuming that your monitoring system notices the problem. All too frequently, you'll notice the problem in some other way. Monitoring systems are designed to detect the things you knew might happen, and problems similar to those. There will be blind spots, it's just unavoidable.