The most common and most likely answer to this crossword clue is the 8 letter word BEDSOCKS
I've seen this crossword clue in The Guardian
B
E
D
S
O
C
K
S
Buddy explains!

The straight part
We know that "retirement cover" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case retirement cover = bedsocks.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does BEDSOCKS mean?
BEDSOCKS noun- A sock worn in bed, to keep the feet warm.