Self-indulgent people for a few years, crazy, rejecting union (9)

I believe the answer is:

decadents

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'self-indulgent people' is the definition.
'decadents' can be an answer for 'people' (decadent is a kind of person). I'm not certain of the 'self-indulgent' bit.

'few years crazy rejecting union' is the wordplay.
'few years' becomes 'decade' (I've seen this before. I am not sure about the 'few' bit.).
'crazy' becomes 'nuts' (nuts can informally mean crazy or mad).
'rejecting' suggests deleting specific letters.
'union' becomes 'U' (common abbreviation as in 'Trades Union Congress').
'nuts' with 'u' taken away is 'nts'.
'decade'+'nts'='DECADENTS'

'for a' is the link.

Can you help me to learn more?

I've seen this clue in The Daily Express.

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