You might find yourself in the position where you need to e.g. restart your device but you're not able to do so until a certain time e.g. users using Internet connectivity.

A simple workaround is to add a command to the contable to do this for you:

cru a reboot-one-off "0 5 * * * /sbin/reboot"

This command above will restart your device at 5am. The time syntax is the standard unix cron one.

NOTE: this is effective but not saved permanently anywhere in the confi, hence after reboot the sheduled activity will automatically disappear.