I personally keep /home on a completely separate drive; I have an NVMe SSD for / (root partition, where the OS is installed) and /home lives on a SATA SSD. There’s a page in the install process that lets you do this, create partitions on various devices, or select existing ones.
Having /home on a different partition means that you can swap out the root partition from around it to repair or replace the OS and you don’t have to move your files around. It makes the process of recovering from certain kinds of calamities and the process of distrohopping a lot faster.
Having them on a completely separate drive like mine does a couple things, the main one is it adds “drive failure” to the list of “certain kinds of calamities” I can quickly recover from. I can swap out a dead system drive for a new one, reinstall the OS in about 15 minutes, and then just run a little utility to reinstall all my software automatically. My files and settings are all still there.
Here’s the thing no one tells beginners: You’re familiar with hidden files on Windows? How you can right click a file and click “Hide” and it disappears from the list unless you go up to View > Show Hidden Files then it reappears and its icon is blurry? Linux has a similar system for hiding files. To hide a file in Linux, you put a period at the beginning of the file name. In a GUI file manager you can show them similarly to how you do it in Windows, in the terminal you ls -a (dash a for “all”). The Linux ecosystem uses this heavily for app config files. If you ever uninstall software, reinstall it, then notice your settings are still there…this is why. It’s stored in a hidden file somewhere in your /home directory, probably inside of ~/.config.
When I was a beginner, I specifically backed up my Documents, Downloads, Music, Videos etc. folders. And when I had to occasionally restore something from a backup, not only did I have to reinstall everything, but I had to reconfigure all my apps from scratch. Understanding the above paragraph, I backup or maintain my entire /home drive, and when I install a new OS all my settings are already there, including my preferred theme and wallpaper.
I’ll try to tell a shorter version of this story: My father bought his most recent computer, a Dell XPS tower. He got it set up, and the process of moving out of his old one and into his new one, just transferring files, installing software and configuring everything took him a solid two weeks of manual work. In that same time, I ordered the parts for my computer, waited for them to be shipped, assembled the machine, installed the OS on bare metal, restored a backup of my /home folder from my old computer, ran this utility which took a list of all the software I had on my laptop and then installed it all from the package manager automatically, and I was up and running. What he did in two weeks of hands-on work I did in three hours of mostly doing something else while the computer transferred data from an HDD or the internet.