Bad rules - fancy they'll be around for some time (8)
I believe the answer is:
Here is my best explanation:
'they'll be around for some time' is the definition.
I can't tell whether this defines the answer.
'bad rules fancy' is the wordplay.
'fancy' is an anagram indicator.
'badrules' with letters rearranged gives 'DURABLES'.
(Other definitions for durables that I've seen before include "Goods likely to long-wearing" and "Consumer goods that are not destroyed by use".)