But that's an entirely analytical way of thinking about it! You're looking at the decision process and asking if the marginal return on investing another unit of time in it, in terms of the improvement of the goodness of the selected outcome, is greater than the return on using that unit of time in some other way.

The very term "overthinking" implies that there's a right amount of thinking for any decision, so your real problem is working out how much thinking to do.