I did a search for "update-notifier criteria used for determining when to update" but did not find anything.
I have always been curious about the criteria used to determine when an update is needed when those popups say an update is available. Do you want to download and install?
I am using Ubuntu Mate 20.04.
The criteria depends on what you do with your computer.
If you only use it to play, then don't update anything. Unless you're having problems with a game that depends on a new video driver or update.
If you handle sensitive information, especially of an economic nature, you must install all security updates, and have only the absolutely necessary software installed on your PC, in other words, no videos, games, and browsing websites of dubious origin.
For the rest, this rule applies: "if it ain't broke, don't break it" which means: if firefox, for example, works fine for you, then leave it like that, without updating.
Every update is a potential risk of problems, if you're asking something like this, it means you don't have enough knowledge to update indiscriminately.
Now, if what you want is to learn, then start by learning how to recover and install a linux system, and then apply another rule: "If it's not broken, then break it..."
