A word is used "correctly" when the average hearer will be affected by it in the way intended. This is a psychological, not a literary, definition of "correctness". The literary definition would substitute, for the average hearer, a person of high education living a long time ago; the purpose of this definition is to make it difficult to speak or write correctly.
We can never be prepared for everything. No one person can anticipate all of life. In fact, overpreparation is yet another way to wall ourselves in from life.