The comments in the copybook, SPOOLHK.CPY explain the field values:
05 ws-run-frequency pic 99999 value 1
05 ws-keep-for pic 99999 value 6
This is the default retain period and applies to ALL spool output, taking precedence over any class-specific retain periods that are greater than this value. It also determines the retain period for JESYSMSG spool files, making it possible to see jobs in the spool job list even when all their other spool files have been deleted due to a shorter class-specific retain period.
Change the value of ws-keep-for to the maximum number of days that you wish to keep spool output for. (This includes: i) Any held output for SYSOUT classes with no specific retain period ii) Any output that was scheduled for printing which is still in the spool print status)