Taken for granted is an idiomatic phrase, widely used in the Anglosphere in multiple related senses.
The two most prevalent meanings of the expression are somewhat related; firstly, “taken for granted” may signify a lack of appreciation, as someone undervalues a thing with their actions due to thinking it will always be available.
It may also be applied in the sense of completely believing and accepting a statement.
While the exact origin of “taken for granted” is not known, the expression rose from the term “grant” which has been used synonymously to “acknowledge” in English since the 14th century.
The phrase started arising in the 16th century, to express blind faith toward a statement.
By the early 1600’s, “taking for granted” has appeared in numerous literary texts, providing documented cases of the early use of the idiom.
It was also around this time, that the phrase took on a more adverse connotation, as it started conveying that someone makes judgement without critical thinking.
“Taken for granted” started emerging in its current form in the 19th century, when people would start applying the verb’s past-participle form, especially in relation to ideas and objects.
During this same period, the meanings of the expression also expanded, as it would be used in wider and more descriptive contexts, such as assuming the qualities of people.
By the 20th century, the expression also started conveying underappreciation toward ideas, things and especially people.