When: Regularly per housekeeping schedule
SAS Viya 4 does not currently have its own full-featured job scheduler, in the same way that SAS 9 was able to use Platform Suite for SAS. However, it does have a simple time-triggered scheduler for one-shot jobs, which is used for running backups, data loads, and custom jobs created in SAS Data Explorer, SAS Data Studio, and SAS Visual Analytics. See the section on Jobs Flows in the SAS Viya Environment Manager User's Guide for more details.
Check the Jobs page in SAS Environment Manager regularly - e.g. daily - to determine which jobs are scheduled and whether they ran successfully or exited with another state (canceled, failed, timed out, and so on).