Security updates are important and need to be installed regularly and as quick as possible.
In Linux distributions like Ubuntu and Debian this is easily done with the apt package manager. Most of the security updates can be installed without rebooting your system. If you upgrade your Kernel it is required to restart your system and Ubuntu and Debian can tell you if a reboot is required. In case you have a fleet of machines to maintain, OpenNMS and Net-SNMP can help you with this task.
This is an example how to get your systems up to date and let OpenNMS tell you when a reboot of your systems is required.
Would you like to know more? -> Reboot & Update Monitor