Conditions laid down for schoolkids' work periods (5)
I believe the answer is:
terms
I believe this clue is a double definition.
'conditions laid down' is the first definition.
(as in the terms of a contract)
'schoolkids' work periods' is the second definition.
(school terms)
'for' is the link.
(Other definitions for terms that I've seen before include "Conditions (contract)" , "Academic periods" , "Phrases" , "Stipulated requirements" , "qualifications" .)