Some things in a system should happen regularly, on a schedule, by themselves, with no one triggering them. Scheduled actions are how. This piece is about scheduled actions and cron jobs in Odoo.
What a scheduled action is
A scheduled action, in Odoo, often called a cron job, is something set to happen automatically on a regular schedule. Rather than being triggered by a user or by an event, a scheduled action happens by itself, on its schedule, every so often, as set. The scheduled action is, in essence, a defined thing that the system runs, regularly, on its own.
Why scheduled actions are needed
Scheduled actions are needed because some things in a system genuinely should happen regularly, on a schedule, regardless of any user or event. There is regular, recurring work that the system should do by itself, periodically. If such recurring work depended on a user to trigger it, it would depend on someone remembering, and it would not reliably happen. A scheduled action makes it happen reliably, on its schedule, by itself. Scheduled actions are how Odoo handles the recurring, periodic work a system needs done without anyone having to trigger it.
How scheduled actions work
A scheduled action is defined with what it should do and the schedule on which it should happen, how often, and then Odoo runs it on that schedule. Each time the schedule comes around, the scheduled action runs, automatically, doing its defined thing. The recurring work happens because the scheduled action is set to make it happen, regularly and reliably, rather than depending on anyone.
Scheduled actions and the rest of Odoo
Scheduled actions are part of how various recurring things in Odoo happen. Things in Odoo that need to happen regularly and by themselves are handled by scheduled actions, within Odoo itself and in what developers build. A developer who builds functionality that includes some recurring, periodic work that the system should do on its own uses a scheduled action for that work, so it happens reliably on its schedule.
Set scheduled actions sensibly
An honest note. A scheduled action should be set up for genuine recurring work, with a sensible schedule, often enough that the work is done when it should be, not so often that it runs needlessly. A developer setting up a scheduled action should set it for genuine periodic work and on a schedule that genuinely suits how often the work needs doing. Set sensibly, scheduled actions reliably handle a system's recurring work; set without that thought, they can run needlessly or not often enough.
The takeaway
Scheduled actions in Odoo, often called cron jobs, make something happen automatically on a regular schedule, by itself, with no one triggering it. They are needed because some recurring, periodic work genuinely should happen regularly regardless of any user, and depending on someone to trigger it would be unreliable. A scheduled action is defined with what it does and its schedule, and Odoo runs it on that schedule. A developer uses scheduled actions for genuine recurring work, set on a sensible schedule. For how we approach Odoo, see our ERP practice.