For all intents and purposes is an example of a cliche.
Clichés’ are commonly used or overused expressions in the English language.
For all intents and purposes is the usual form of the phrase meaning in every practical sense. For all intensive purposes is a fairly common eggcorn derived from the original phrase. It’s often heard in speech, but it is not usually found in published writing because it generally doesn’t pass through the editorial proces.
A cliché refers to an idea or phrase which has been used so much that it is no longer interesting or effective or no longer has much meaning.
