At eight in the morning, sitting on the bus heading to work, Nusrat — a pseudonym — suddenly noticed a tiny pendant hanging from her colleague's neck. It was no piece of jewellery. "What is that?" she asked. Her colleague smiled and said, "It listens to the conversation around me all day, and at the end of the day it writes a summary on its own — what was said in each meeting, what promises I made to whom, everything." Nusrat felt a mix of surprise and discomfort. This device was listening to her words too, without ever asking for her consent.

That little pendant is actually the newest trend in the world of technology: wearable AI. The world's biggest tech companies are now investing in devices meant to be worn on the body at all times — positioned as the next step after smartphones — which draw directly on the conversation around them for assistance. One major company is working this very year toward a sales target of around ten million such devices, and its new series of smart glasses is reaching the market model after model; another three or four models are due in the coming months. That same company alone sold nearly seven million smart glasses last year — a sign of just how fast this market is growing.

Instead of typing questions into a phone, these devices assume the user will stay connected to AI throughout the day — through speech, through what they show the device, even through eye gestures. Meeting summaries, to-do lists, even recovering lost information — all of it is now possible with a single device worn around the neck or on the eyes. Companies are also planning to sell these devices to workplaces at scale through a dedicated enterprise service, where individual organisations buy more than a hundred devices at a time and hand them to their employees.

  • These devices do not just listen to you — they also record everyone around you, and those people may have no idea their words are being captured and stored.

  • Earlier attempts to bring such devices to market failed, largely because of users' privacy concerns and because the devices' real-world usefulness did not live up to expectations.

  • Where continuously recorded conversations are stored, how long they are kept, and how they might be used in the future remain unclear to many users.

  • A person wearing such a device in an office or family setting is, in effect, making everyone around them part of a form of surveillance without their knowledge.

  • The hardware divisions of major tech companies have been running losses for years. The pressure to hold on to the market can mean security and privacy considerations are handled in a hurry.

  • However tempting the convenience, recording the words of everyone around you without their knowledge is by no means a small matter.

A similar kind of AI pin appeared on the market a few years ago, clipped to a shirt or worn around the neck, delivering information around the clock. But that company effectively vanished from the market over privacy concerns, problems with the device overheating, and a failure to match what users truly needed. The difference this time is that the new companies are not trying to invent something entirely new; they are building on a product that is already popular. One company, for example, is pursuing a partnership with a famous fashion brand for its smart glasses, so that people accept the product as an ordinary everyday item before they even think of it as technology. Yet the question remains: has the fundamental privacy problem truly been solved, or has it simply been wrapped in a prettier package?

1. Before using such a device at work, check your organisation's policy — it must be clear what information is retained, and what happens to that information when an employee leaves.

2. When speaking with others, telling them whether the device is recording is basic courtesy — and in many places a legal obligation. Use the device accordingly.

3. Build the habit of switching the device off during sensitive conversations, such as family, medical or financial matters.

That afternoon, on her way home from the office, Nusrat decided that if she ever bought such a device, the first thing she would do is tell her friends: "If you talk to me, the AI may be listening and recording — beware." A few days later she did buy herself a pair of smart glasses, but she set one condition from the start: before sitting down to any personal conversation, she would take them off.

So is this ever-listening device a companion for life, or an enemy of our privacy? In truth, it can be both at once. The question is not about technology at all. The question is how much listening we allow, and from whom.