Managed devices that are awake and connected to the internet check in with Fleetsmith about every five minutes. Devices check in periodically to receive apps and settings that have been configured in the Fleetsmith Admin Console or to update those apps and settings.
Fleetsmith Admins can't force a device to check in with Fleetsmith, but if the device is awake and connect to the internet it should check in on its own periodically.
You can read more about what do to if a device isn't checking in here.
On the Device Details page, hovering over the last check-in will display the exact time and date that a device last checked in: