The most common and most likely answer to this crossword clue is the 6 letter word REPAIR
I've seen this crossword clue in Financial Times
R
E
P
A
I
R
More clues leading to the result REPAIR
Buddy explains!
The straight part
We know that "Maintenance" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case maintenance = repair.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 REPAIR mean?
REPAIR noun- The act of repairing something.
- The result of repairing something.
- The condition of something, in respect of need for repair.
- To restore to good working order, fix, or improve damaged condition; to mend; to remedy.
- To make amends for, as for an injury, by an equivalent; to indemnify for.
- The act of repairing or resorting to a place.
- A place to which one goes frequently or habitually; a haunt.
- To transfer oneself to another place.
- To pair again