How demand changes by end of season for used kit (4-2-4)
I believe the answer is:
hand-me-down
'used kit' is the definition.
(second-hand clothing)
'how demand changes by end of season' is the wordplay.
'changes' indicates anagramming the letters.
'by' means one lot of letters go next to another.
'end of' says to take the final letters.
The last letter of 'season' is 'n'.
'how'+'demand'='howdemand'
'howdemand' is an anagram of 'handmedow'.
'handmedow'+'n'='HAND-ME-DOWN'
'for' is the link.
(Other definitions for hand-me-down that I've seen before include "Garment passed on to another" , "Passed-on clothing" , "Item passed on" , "Second-hand garment" .)