While the availability check is not strictly a metric, it does have a collection schedule that can be edited with the other metric collection schedules.
Click the Inventory tab in the top menu.
Select the resource category, such as servers or services, in the Resources menu table on the left. Then browse or search for the resource.
Click the Monitoring tab on the resource entry.
Click the Schedules subtab.
Select the availability metric, and enter the desired collection period in the Collection Interval field, with the appropriate time unit (seconds, minutes, or hours).
Availability schedules can be set on compatible groups or resource type templates. Setting it at the group or resource type level changes multiple resources simultaneously.