> The real problem is that the ability to come up with a good napkin math estimate for a technical problem doesn't correlate with the ability to actually do the

> The real problem is that the ability to come up with a good napkin math estimate for a technical problem doesn't correlate with the ability to actually do the job to solve the problem. I don't think this is true at all. There have been many times where I've estimated numbers to come up with a "scale" number ... which was important in other ways. How many servers are we likely to need? How many connections per second are we likely to see? How much memory is this likely to take up. Depending on the context in which you need to know the answer, estimating a value can be extremely useful. It can point you towards the right "group" of solutions that you should consider.