Routine all week long? (8)

I believe the answer is:

everyday

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'routine' is the definition.
(synonyms)

'all week long?' is the wordplay.
'all' becomes 'every' (similar in meaning).
'week long?' becomes 'day' (I can't justify this - if you can you should give a lot more credence to this answer).
'every'+'day'='EVERYDAY'

Can you help me to learn more?

(Other definitions for everyday that I've seen before include "Common or usual" , "Quotidian" , "Ordinary, for regular use" , "Mundane, ordinary" , "familiar" .)

I've seen this clue in The Times.

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