The most common and most likely answer to this crossword clue is the 8 letter word SERVICES
I've seen this crossword clue in Independent
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More clues leading to the result SERVICES
Buddy explains!

The straight part
We know that "Maintains" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case maintains = services.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 SERVICES mean?
SERVICES noun- An act of being of assistance to someone.
- The practice of providing such a service as economic activity.
- A department in a company, an organization, a government department, etc.
- A function that is provided by one program or machine for another.
- The state of being subordinate to or employed by an individual or group
- The military.
- A set of dishes or utensils.
- The act of initially starting, or serving, the ball in play in tennis, volleyball, and other games.
- A religious rite or ritual.
- The serving, or delivery, of a summons or writ.
- (Israel, West Bank, also in Jordan, Lebanon and Syria) A taxi shared among unrelated passengers, each of whom pays part of the fare; often, it has a fixed route between cities.
- A musical composition for use in churches.
- Profession of respect; acknowledgment of duty owed.
- The materials used for serving a rope, etc., such as spun yarn and small lines.
- To serve.
- To perform maintenance.
- To inseminate through sexual intercourse
- To perform a sexual act.
- Service tree