Obsession
How does hiring servants on a pass turn work, and is it required?
The expansion rulebook sets out the rule and the designer confirmed the details in several threads.
On a pass you reclaim your discard pile, refresh all service, then choose one of three options: collect £200, hire servants, or refresh the market. Hiring uses the Butler's Room tile with the Butler (or Underbutler) as normal: you take two servants and the tile flips on first use. Refresh comes before hire, so the Butler is always available, and the Butler plus new servants end in Expended Service. The rule is required with Upstairs, Downstairs and optional in the base game, where the original hire rule stays the default; the designer notes servants run out faster in the base game.