Advertising strategy devoid of ideas and such like, and too old (7,8)
I believe the answer is:
blanket coverage
'advertising strategy devoid of ideas' is the definition.
I can't tell whether this definition defines the answer.
'and such like and too old' is the wordplay.
I cannot really understand how this works, but
'and' could be 'n' (common abbreviation for 'and') and 'n' is found in the answer.
'old' could be 'overage' (similar in meaning) and 'overage' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for blanket coverage that I've seen before include "Comprehensive reporting" , "after snowstorm" .)