Volunteer firefighters in cities are often used to fill up the rows of the paid ones or to relieve them, so they can return to standing by for the next alarm an

Volunteer firefighters in cities are often used to fill up the rows of the paid ones or to relieve them, so they can return to standing by for the next alarm and ensure short reaction times. That's at least how it works in the city where my brother is working as a firefighter and I think it's comparable all over Germany.