[Shandrax]

I disagree with Aaron for one simple reason: You don't need precise calculations based on pure assumptions to get an approximation for the correct play, because this is where your experience will bail you out. A good player will recognise a really bad play and won't make it. Once it's a close decision between two plays though, you usually cannot make a substantial mistake.

The decision process on problematic hands where you cannot make a substantial mistake cannot be improved by guessing, because guessing wrong may result in an even bigger mistake. In other words, if you are working with a small margin of error, you shouldn't add additional uncertainty by starting to guess. You would simply have to guess right way too often.