When one might spend savings always on the ultimate in Bobby Darin compilation (5,3)
I believe the answer is:
rainy day
'when one might spend savings' is the definition.
I can't tell whether this definition defines the answer.
'always on the ultimate in bobby darin compilation' is the wordplay.
'always' becomes 'ay' (archaic term for 'always').
'on' means one lot of letters go next to another.
'the ultimate in' suggests the final letters (take the ultimate ie last letter).
'compilation' indicates anagramming the letters (letters compiled or organised differently).
The final letter of 'bobby' is 'y'.
'y'+'darin'='ydarin'
'ydarin' anagrammed gives 'rainyd'.
'ay' after 'rainyd' is 'RAINY DAY'.
Can you help me to learn more?
(Other definitions for rainy day that I've seen before include "Save for this future time" , "One should save money for a . . . . . . . . - may need it to buy umbrella" , "Time of financial need" , "One saves up for it" , "Wet time" .)