Where they earn their place
The common cases are a fixed button under a reception desk or till, a portable one for somebody working alone, and a unit in the home of an elderly or vulnerable relative.
What they have in common is that pressing a button has to be faster and less conspicuous than getting a phone out and explaining a situation to somebody.
Monitored or audible
An audible panic alarm makes a noise where it is, which is often enough to interrupt what is happening. A monitored one signals an alarm receiving centre, which can escalate to keyholders or the emergency services.
Which is appropriate depends on who is meant to respond and how quickly. We will talk that through rather than default you to the more expensive option.
Personal and medical alarms
The same thinking extends to personal alarms, carried rather than fixed to a wall, and to medical alarms: a button that notifies friends and family, or an ambulance, when somebody needs help.
If you are looking at one for a relative, the useful decisions are about who gets notified and what happens next. That is a conversation, and the survey is free.
Alongside an existing system
Panic alarms can usually be added to an intruder system already installed rather than run as something separate, so there is one system to arm, test and service.
If the existing panel is somebody else's, we would want to look at it first.