I don’t back up anything I can rebuild. I have multiple half-assed methods in use together for the rest of it:

• Backups daily of homedirs on desktops and laptops using Borg and Vorta to external usb drives. These devices get rotated out annually. I used to run 2-disk RAID1 and when I rotated the disks out, split them and sent them to family but now I’m taking my chances on having them local and putting them in a fireproof box.
• Code repos are synced to github or srht.
• Monthly backups of homedirs are sent via borg to rsync.net.
• Desktop and laptop homedirs get periodic (roughly monthly) burns to Dual-Layer BDRs which I put in the fireproof box and sometimes hand off to family.

This desktop right here (running a couple of ZFS pools) has drives with more than 3 years on it…

$ for d in $(find /dev/sd[a-z]); do sudo smartctl --all --json $d| jq -c '[.model_name,(.power_on_time?.hours?/8760)]' ; done
["CT1000MX500SSD1",2.2034246575342467]
["WDC WD140EDGZ-11B1PA0",0.3791095890410959]
["TOSHIBA HDWE140",4.040639269406393]
["TOSHIBA HDWE140",5.925684931506849]
["WDC WD80EMAZ-00WJTA0",3.359246575342466]
["TOSHIBA HDWE140",5.925684931506849]

runs like a top (better not jinx myself).