RQM 4.0 : Purpose of "PrintJobReaper Delay" value
One answer
The PrintJobReaper evaluates which print jobs in the repository have expired and removes them from the repository so they no appear in the Manage Export Job Queue view. The delay defines the number of seconds between runs of the PrintJobReaper. Decreasing the value will cause the PrintJobReaper to run more often (negligible performance impact) but keep the Manage Export Job Queue view free from expired print jobs.