Defaults are a starting point
Templates help the owner avoid blank-page setup. They should not create false confidence.
Every interval should be editable and clearly marked when owner-overridden.
Vendor recommendations matter
If an invoice or report recommends a follow-up interval, that recommendation should be visible during review.
The owner can then decide whether to update the schedule.
Use records to keep schedules current
When an event is confirmed, the next due date should move from the actual service date.
That keeps the schedule anchored in history.