Is the dot structure method failproof? in other words, are there any exceptions or is this the best way to determine oxidation states for "non-obvious" compounds?

This _is_ the best method to determine the oxidation states for non obvious compounds as far as I know.

However, dot structures are not perfect; for instance, they are really useful for simple mechanisms, but fail to explain to explain the behaviors and regioselectivity of other reactions (such as Wittig reactions for instance).

They are like other investigations? say there was a murder u have to do blood test and finger prints which run through a lab.