See T93040 for some discussion around this - essentially weird stuff happens on the cluster. Its life. The saneitizer's job is to clean up weird stuff. Should we continue to run it manually when we think that something weird happened or just run all the time?
Stakeholders: Cirrus operators
Benefits: This could keep the cluster in a more sane configuration. Or it could hide errors.
Estimate: A week. Probably less, but its a cron change and those can get funky.