What's the difference between apt full-upgrade and apt upgrade when this site says to use both commands?

This guide says to use both commands before installing stuff. Is it true that I should use both commands? Both commands install packages right?

The common difference between upgrade and full-upgrade is that a full-ugrade will remove the installed packages if that is needed to upgrade the whole system.

I will do a full-upgrade if I am intending to to a big upgrade to my Linux systems.

Linux apt-get commands

The difference between upgrade and full-upgrade is that the later will remove the installed packages if that is needed to upgrade the whole system. Be extra careful when using this command

You need to use care lest you remove (with full-upgrade) packages you did not intend to be removed.

I will more frequently use Autoremove (sudo apt autoremove) to remove old packages and then just use upgrade.

It is not necessarily hard and fast.

The article I posted above is good to read through entirely.

If I need to do an aggressive cleanup or a bit of a repair before further upgrades, I will run:

sudo apt-get update && sudo apt-get autoclean && sudo apt-get clean && sudo apt-get autoremove

I hope that helps.