Automations are repeatable actions carried out at timed intervals. The difference between actions and triggers is that triggers execute actions when creating, updating, and removing elements.
Imagine you want all companies with a certain marketing score, and number of employees or revenue, be assigned to a role.
Simply tell the automation to look whenever a company is updated with the minimum marketing score you have set, and check if the revenue and number of employees fields has the right value. If so, assign them to the role.
You can also add other actions. For example, creating activities for the assigned users with the company, or emailing a user telling them that the company has reached the marketing score level.
Instead of relying on a user to do this manually, the automation automatically takes care of it.
Jobs that perform an automation are run approximately every 2.5 hours.