I must have badly messed up with my configuration a few months ago, and in due time I now realise all systemd timers are disabled.
Now I have to guess which ones to enable, and I have little clue whether each single one of them is useful, resource-intense, or dangerous (for example, I remember having read automatic trimming on SSD storage might have side effects).
I would appreciate suggestions on single timers, on all of them, or even just a snapshot of which are the default settings on OpenSUSE Tumbleweed.
My own snapshot (systemctl list-unit-files --type=timer):
UNIT FILE STATE
backup-rpmdb.timer **disabled**
backup-sysconfig.timer **disabled**
btrfs-balance.timer **disabled**
btrfs-defrag.timer **disabled**
btrfs-scrub.timer **disabled**
btrfs-trim.timer **disabled**
check-battery.timer **disabled**
chrony-dnssrv@.timer **disabled**
fstrim.timer **disabled**
fwupd-refresh.timer **disabled**
lifecycle-report.timer **disabled**
logrotate.timer **enabled **
mandb.timer **disabled**
mdadm-last-resort@.timer static
mdcheck_continue.timer **disabled**
mdcheck_start.timer **disabled**
mdmonitor-oneshot.timer **disabled**
packagekit-background.timer **disabled**
shadow.timer static
snapper-boot.timer **disabled**
snapper-cleanup.timer **disabled**
snapper-timeline.timer **disabled**
systemd-tmpfiles-clean.timer static
xfs_scrub_all.timer **disabled**
(logrotate is the reason I realised the issue, so I suppose there are good reasons to enable it).