Assumed 'great' often drank unfortunately (5,3,7)

I believe the answer is:

taken for granted

'assumed' is the definition.
(taking for granted is a kind of assuming)

'great often drank unfortunately' is the wordplay.
'unfortunately' indicates an anagram.
'great'+'often'+'drank'='greatoftendrank'
'greatoftendrank' anagrammed gives 'TAKEN FOR GRANTED'.

(Another definition for taken for granted that I've seen is " valued too lightly".)

I've seen this clue in The Independent.

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