I want to keep sending the alerts out as long as the problem exists; otherwise, it may be viewed as a transient problem. Shifting to a longer polling frequency helps prevent overloading the responding team with alerts. One web application is used to register volunteers for disaster response and it is also used during disasters; the state agency where I work is a first responder for disasters, setting up shelters and taking care of health needs. For that service, I added a "Hurricane Mode" where it uses the normal working hours polling schedule for the weekends and after hours as long as the state's Emergency Management Division is activated.
Polling interval: Normal hours: 10 minutes, error detected: 60 minutes. After hours, weekend, holidays: 4 hours, error detected: 8 hours.