wikipedia is not without controversies in its reliability. However, in general, if you are a learned man, and read it frequently, you basically know by heart which parts is not trustworthy.
when you are a learned man (as in, you have several degrees, or is a scholar, and often minimally knowledgeable in diverse fields from sciences to humanity, such as philosopher), you can basically tell when you read something that came across as funny, wikipedia or not. Because, you know what you know and what you don't know, and you have good experience of seeing questionable writing.
And, if you do use wikipedia a lot, you also know which type of article, or part of the writing style, is red ink.