## 1 Introduction  
The relationship between humans and technology is best exemplified through wearable technology, which increases human potential through the provision of smart gadgets that can help to monitor and track body parameters. Wearable devices provide continuous monitoring of an individual's health, activity, and fitness, which has significant potential for enhancing human activities and standard of living. There are sensors embedded in these devices that gather personal information and exchange this information through Wi-Fi, Bluetooth, cellular technology, etc. [1]. Wearable technologies offer a wide range of functionalities for unobtrusive health monitoring, such as heart rate tracking, blood sugar tracking, blood pressure analysis, gait analysis, sleep score, as well as a variety of other health factors. These devices are the subject of extensive research [2] and can measure physical activity, such as steps walked, calories burnt, or workout intensity, using a bracelet-like gadget worn on the wrist. Then, the data are transmitted to a mobile application, either wirelessly through Bluetooth synchronizing or through the connection of the device to a smartphone, where objectives, progress, and activity may be recorded [3]. The most widely used wearable devices are wrist-worn smartwatches, which can receive and send notifications, messages, or calls. For example, the Apple watch series can receive incoming calls and has a comparatively large screen, but is more expensive than other smartwatches. The mainstream wrist-worn devices include the Apple watch, Samsung Gear S, Mi Band, Huawei Honor, Fitbit Surge, and Jawbone Up3, with many others available for purchase. Currently, the major aspects of wearable devices are extensively researched, such as the dependability and accuracy of evaluation. Recently, researchers have raised concernsregarding the long-term usage of wearable devices, highlighting the importance of combining behavioral change approaches such as goal setting, feedback, and rewards with other evidence-based techniques [4]. In addition, whilst wearable technology has a wider range of potential applications, users do face usability issues with these devices [5]. Furthermore, studies have found that the acceptability of wearable items for regular consumers, as well as their comfort level, is critical to a product's success [6]. For these reasons, it is necessary to identify and address the usability issues of wearable devices because the success of these devices relies on users' product experience. As user experience is one of the core aspects contributing to a product's popularity, it is crucial that the device performs its functionality in an easy, comfortable, and intuitive way. Therefore, continuous usability testing is essential to observe users as they interact with a product or prototype and ensure a satisfactory user experience, contributing to the widespread and quick adoption of wearable devices. Usability is a multifaceted concept that can be explored in various ways. The term \"usability\" has been used extensively for the past few decades, and various individuals interpret it differently. Some people associate usability with ease of use or convenience and examine it from the standpoint of an interactive interface; meanwhile, others refer to usability as a conceptual scale for the real-time evaluation of a product's functionality obtained from feedback from potential users [7]. Therefore, despite the testing paradigm, usability testing assesses a product's ability to fulfill its intended functions. Food, consumer items, websites or web applications, computer interfaces, papers, and electronics are all examples of products that benefit from usability testing. There are various factors in developing usability criteria. According to Nielsen, usability has five key characteristics: learnability, satisfaction, efficiency, low mistake rate/quick error recovery, and memorability [8].