https://www.reddit.com/r/fatFIRE/comments/o9axky/how_do_you_hire_a_maid/
Most services you can pick the frequency (every week, every 2 weeks) and you pay either per hour or per full cleaning session.

http://inhousestaffing.com/domestic-staffing/household-staffing/housekeepers/
How much does it cost to hire a housekeeper through an agency? At Aunt Ann's In-House Staffing, our unique fee structure sets us apart from other ...

https://www.mollymaid.com/why-hire-us/
With our long-running reputation for professionalism, dependability, flexibility, and affordability, you can be sure hiring us is the best decision you can ...