Disk management
Resiliency
If you're an openSUSE or RedHat user, you are likely using Btrfs for your root filesystem. Good job, you picked a safe, resilient and performant filesystem for your core OS.
ZFS offers most things you find in Btfrs and much more, and for a while it was only easily ported to systems like illumos. See also: Wiki:illumos. Support for ZFS on Linux is here today with OpenZFS, which I have yet to test myself.
If you don't need such robust features, XFS is a better filesystem for you and will give you greater performance. The exts tend to work and have great compatibility with repartitioning strategies found in gparted. However, after seeing XFS and how it holds up in production, I feel comfortable using XFS over any ext filesystem. Just plan it out well, especially if you are using one drive, I would recommend formatting the bulk of it as XFS.
My root filesystem can fit comfortably in 40GB since at least 2016. This only requires good tuning of the # of kept snapshots in snapper.
So if I have only a 1TB drive, I would allocate 960GB as XFS.
Cleanup
Any modern consumer of media from the Internet knows how easy it is to fill up devices. Be smart, don't buy a new device simply because of this problem. Software can help us. But don't fall into the trap of specialized disk cleanup programs, which have trouble keeping up with configs and locations of the myriad of software we use today.
Use qdirstat, which will help you easily identify and remove unwanted files, which ensures you can use the same drives for an extended period of time (years). If you happen to be a Windows user, the equivalent program is called windirstat. Windows users may want to try the bite-sized diskitude.
MacOS users can look at GrandPerspective1.
openSUSE Cleanup
openSUSE has a page on cleanup strategies for specific tools such as snapper, systemd logs, etc.
If you installed openSUSE Tumbleweed before Aug 6, 2020, you should migrate your tmpfs setup. The distro now uses shared memory for the tmpfs.2.