LXLE utilizes automatic security updates and installation by default; doing so in the background during idle time.

All other updates are performed by checking the update manager located in

Menu>System Tools>Update Manager

To save memory there is no update “checker” daemon running in the background. Between automatic security updates and your own boredom/memory to check for updates, your system should be just fine, why waste resources when you can just check every once in a while.