There's no advantage in breaking it (4)
I believe the answer is:
even
'advantage in breaking it' is the definition.
I can't judge whether this defines the answer.
'there's no' is the wordplay.
'there's' becomes 'eve' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'no' becomes 'n' (common abbreviation).
'eve'+'n'='EVEN'
Can you help me to learn more?
(Other definitions for even that I've seen before include "Equally balanced; level" , "Flat, regular" , "end of the day, reading poetry" , "Regularly; yet" , "Flat - yet" .)