Separating the NPCs into three types.

You can hire workers and troopers for a specified period of time for a specific number of credits, paid upon purchase of contract. Troopers cost more and last the least amount of time, but come equipped with their own weapons, and workers cost the least and last the longest.

Troopers will NOT require a bed but will require ammunition.

Colony Workers WILL require a bed each and can perform simple tasks.

Visitors will have contracts that show up and require a room/bed of their own for the period of time specified, after which they pay you credits equal to the number of days they stayed and whatever other factors you want to add.