The core.source_info_internal gets the days_until_expiration value is set by the collection sets. 730 days is the default for the disk_usage collection and usually this isn't causing too much growth.

In my experience the collections sets "Server Activity" and "Query History" are responsible for most of the data and the default retention period for these is 14 days.

You can change the retention period by opening the properties of an colletion set.