The settings "YOS" or "Years of Service" on Activity Status is used to count a volunteer's time spent with an Organization
Counts toward YOS (Years of Service)
Once enabled, as long as that volunteer has any activity status with YOS selected, the value will be calculated. For example, you might want to count a status of “In Training” as part of their cumulative service, but omit “On Vacation” periods because the volunteer is not doing active service at that time.
Other options include:
OK to Email
On occasion, there is a volunteer who expresses the wish to never receive email. Or, you may wish to always exclude archived volunteers from email campaigns or automatic emails. Now, these volunteers can be completely excluded from any email correspondence as long as they have an activity status where “OK to Email” is deselected.
OK to Sign In
Allow or prevent a volunteer from signing in to Sign-In stations based on Activity Status.