When operating a VHF marine radio, when should you use the term MAYDAY?

Using the term "MAYDAY" is reserved for situations where there is an immediate threat to life or vessel safety. This urgent call signifies that the person making the call is facing a life-threatening emergency and needs immediate assistance. It is a standard maritime distress signal recognized internationally, and it alerts nearby vessels and coast guard services that urgent action may be required.

In contrast, routine communication, requests for assistance that are not life-threatening, or simple announcements of position do not warrant the use of "MAYDAY." These situations require different terms and methods of communication to avoid causing unnecessary panic or confusion, as "MAYDAY" conveys a situation of extreme peril where every second counts.