By surveying every area a resident might use, with the actual devices, before the system is relied upon - and by re-checking when the building changes.

A coverage prediction is not sufficient. The survey should place a fob at floor level, in bathrooms, at the far ends of corridors, in stairwells and lift lobbies, and outdoors wherever residents go, and confirm the call is received each time.

Bathrooms are the most common problem: tiled walls, metal fittings, and often a position at the far edge of coverage - and they are also where help is most often needed.

Floor level matters because a resident who has fallen is not holding the fob at chest height, and propagation close to the floor is worse.

Additional receivers or repeaters fill gaps, and their positions come from the survey rather than a plan.

Re-survey after building work, new furniture or partitioning, and periodically - coverage is not a permanent property of a building.

By system monitoring that reports low batteries automatically, with a planned replacement regime - never by waiting for a device to stop working.

A fob with a flat battery gives no indication to the resident carrying it. They press it, nothing happens, and they may not understand why.

So the system must monitor battery state and report low levels to staff with enough warning to act. That is a required feature rather than an option.

Many systems also expect a periodic supervision signal from each device, so a fob that has stopped transmitting entirely - flat, broken or lost - is reported as missing rather than silently absent. That supervision is arguably more important than the battery warning.

Maintain a register of devices with their battery replacement dates, and hold stock of the correct type.

Some devices use sealed batteries and are replaced as a unit at end of life, which simplifies maintenance and should be planned for in the budget.

With location capability yes, and without it no - which is the difference between staff attending and staff searching.

A basic fob transmits an identifier. The system knows which resident called and nothing about where they are, so staff check the resident's room and then look elsewhere - which wastes the time that matters most.

Location-aware systems determine the area from which receiver picked up the call, so the alert names a room or a zone. Resolution depends on receiver density: room-level in a building with a receiver per room, zone-level with fewer.

Some systems add location beacons for finer resolution, and outdoor areas may use separate arrangements.

For a resident who moves around, location is not a refinement - it is what makes the fob useful. A fall in a corridor at night, with staff searching room by room, is exactly the scenario the system should prevent.

Specify the resolution required against the building's size and layout.

Light, comfortable, water-resistant and unobtrusive - because a fob that is uncomfortable or stigmatising is left in a drawer.

Wrist-worn devices are the most reliably carried, since they are always on the person. Comfort matters: a heavy or irritating device is removed, and a strap that cannot be adjusted for a thin wrist will not stay on.

Pendants on lanyards suit some residents and are easier to put on and take off, which is both an advantage and a risk - they are more often left behind.

Water resistance is essential. Bathrooms are where help is most needed, and a device removed before showering is not available at the moment of greatest risk.

Appearance affects acceptance. Devices that look obviously medical are worn less willingly than discreet ones, and a device that is not worn provides nothing.

Involve residents in the choice where possible. Compliance is the limiting factor for this product, far more than any technical specification.

By button design and by a response culture that does not become complacent - accidental calls are inevitable and the response must not degrade.

A button that is too easy to press produces calls when a resident leans on a chair arm or rolls over in bed. One that is too hard defeats residents with limited strength - which is the more serious failure.

Recessed buttons and those requiring a brief sustained press reduce accidental operation while remaining usable, and are the usual compromise.

Some systems allow a short cancellation window at the device, so a resident who calls by accident can cancel it - though this must not make genuine calls easy to lose.

The important point is cultural. Frequent accidental calls from one resident lead staff to assume the next is also accidental, and that assumption is where harm occurs. A pattern of accidental calls should trigger a review of the device and its fit for that individual, not a reduced response.

Yes, and many systems provide staff devices alongside resident ones - with a different priority and a different response.

A staff duress call means a member of staff needs immediate assistance, and it requires a faster and larger response than a routine resident call.

Systems distinguish the two by device type and signal them differently - distinct tones, distinct display, and often direct notification to all available staff rather than to a zone.

Location is more important for staff duress than for anything else, because the member of staff may not be able to say where they are, and the response has to arrive quickly.

Where staff duress is provided, the procedure should be defined, trained and tested - who responds, how many, and what they do on arrival.

Confirm the system can distinguish device classes and apply different escalation, since some simpler systems treat all wireless calls identically.

It depends on being worn, on coverage, on a battery, and on the resident being able and willing to press it - and none of those can be assumed.

A fob left on a bedside table provides nothing, and that is the most common failure by a wide margin.

A coverage gap is invisible until a call is made from within it.

A flat or failed battery is silent unless the system supervises the device.

And a resident who is unconscious, confused or unable to press cannot use it at all - which is why fobs supplement fixed call points and, in some settings, automatic detection such as fall sensors, rather than replacing them.

What follows in practice is that the fob is one layer. Fixed call points remain in rooms and bathrooms, routine checks continue, and the fob adds the ability to call from anywhere for residents who can use it.

Designing a system that relies on fobs alone leaves each of those limits as an unmitigated gap.