Of bands never making a comeback, a proportion quits (5)
I believe the answer is:
evens
'quits' is the definition.
(I've seen this before)
'of bands never making a comeback' is the wordplay.
'of' indicates a hidden word.
'making a comeback' is a reversal indicator.
'sneve' can be found hidden inside 'bands never'.
'sneve' written backwards gives 'EVENS'.
'a proportion' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for evens that I've seen before include "Presses" , "In betting, winning the amount staked" , "50-50 chance" , "Oddly, these could be odds" , "Fifty-fifty odds" .)