22 across
Cost
of
maintenance
all
the
way
to
fortification
(6)
Cost of maintenance all the way to fortification (6)
hints
0
checks
0
hints
The definition is at the beginning of the clue.
How the clue works
See Cost of maintenance — that's your definition, meaning the money spent keeping something in good nick. For the wordplay, "all the way" gives you UP, and stick that onto KEEP (a fortification, the stronghold bit of a castle), and you're there.