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New Job as the Plot Demands sounds likes what you are looking for
Macron's notes
Except that throughout the series, Mr. Drucker still runs the general store, and his main job doesn't change.
Wouldn't New Job as the Plot Demands cover someone who changes jobs each episode with little steady employment, e.g. someone working at a fast food restaurant, convenience store, salesperson, retail clerk, janitor, garbage collector, etc.?
Sounds like Sam is a Jack of All Trades.
S.O.L.I.: Code 7 is coming and nobody will stop it. Your salvation is near.
New Jobs As The Plot Demands is mainly a comedy trope where the unlikeliness of switching jobs — lawyer one episode, waiter the next, train conductor after that, etc — is the joke unto itself. That sounds like what you want.
What trope describes someone in a small town who works in various other functions in addition to their regular job?
In Green Acres, Sam Drucker runs his general store and the Hooterville World-Guardian newspaper, serves as a volunteer fireman, notary public, constable, justice of the peace, postmaster, and the mayor.