Due to the large and unsustainable use of valuable natural resources and electronic waste generation worldwide, which poses risks to human health and the environment, different organizations have initiated efforts to shift from a linear economy to a circular economy. A crucial aspect of promoting a circular economy is improving product durability, which can reduce resource extraction and waste because products remain in use for a longer period. Methods for measuring and indexing durability should encourage consumers to buy more durable products and incentivize manufacturers to compete in improving durability.
1. Introduction and Motivation
Electronic waste (e-waste) is a rapidly growing waste stream. In 2019, 53.6 million tons of e-waste were generated globally, estimated to reach around 74.7 million tons by 2030
[1]. A typical mobile phone over its lifetime has a carbon footprint of 60 kg, 85% of which is attributed to materials and the production of the phone. Considering that 5.3 billion mobile phones have been thrown away in the form of e-waste in 2022 alone, with only 17% of its materials recycled, one can appreciate the enormity of e-waste for just one of many electronic products in use
[2]. This considerable amount of e-waste contains toxic and hazardous materials that can harm the physical and mental health of humans. Physical health problems such as miscarriages, changes in thyroid function and development, decreased lung function, and mental issues (such as changes in temperament and behavior) are some of the recognized health issues caused by exposure to e-waste
[3][4]. In addition, water and soil contamination and greenhouse gas emissions leading to global temperature rise are notable examples of e-waste environmental impacts
[5][6]. Therefore, the negative impact of e-waste on the environment and ecosystem is significant and not sustainable.
In addition, a substantial amount of valuable material resources is currently being used for manufacturing electronic and electrical equipment (EEE). EEE contains up to 69 elements, including valuable metals such as gold, silver, and copper and critical raw materials such as cobalt, palladium, and indium
[1]. Generated e-waste from printed circuit boards, which exist in every EEE, contains more than 1000 different substances, including organic material (30%), metals (40%), and ceramics (30%)
[7]. However, just 17.4% of e-waste is formally collected and recycled
[1], so a significant portion of produced EEE will be discarded in landfills. This pattern of producing and disposing of EEE increases the need for raw material extraction, which has substantial health and environmental impacts
[8]. In conclusion, implementing some sustainability goals to decrease the use of limited material resources and reduce the generation of e-waste is desirable.
In the context of products, practical sustainability goals include minimizing the negative environmental impacts of e-products and the excessive use of limited resources. These goals can be attained through smart design and responsible usage
[9]. One such process recently implemented in some countries is transitioning from the current linear economy toward a circular economy. A circular economy aims to create a closed-loop system for the product life cycle and maximize the utilization of materials by employing recycling, remanufacturing, reusing, and long-lasting products. Governments worldwide have recognized the importance of transitioning to the circular economy by enacting laws, programs, and regulations to implement this transition. Examples of such efforts include the Circular Economy Action Plan, which is part of the Green Deal in Europe, France’s Anti-Waste and Circular Economy Law, and China’s Circular Economy Promotion Law.
Consumers’ attitudes expressed by their purchasing choices and behaviors could significantly affect the promotion and adoption of the circular economy through market demand, influencing businesses to adopt more sustainable and circular products
[10][11]. Therefore, it would be essential to enable and inform consumers to support the circular economy by measuring and presenting the degree of circularity of products. One of the key aspects of the circular economy that should be measured is the product’s longevity or, more comprehensively, the ownership risk, which includes both the expected useful life of the product and the manufacturer’s assurance of a minimum life. Extending the lifespan of products reduces the disposal of products and the need to produce replacements. This minimizes both waste generation and the need for extracting material resources, which are critical characteristics of a circular economy.
2. Circular Economy and Role of Product Durability
A circular economy is a strategy adopted by many governmental and private agencies and manufacturers to support resource and environmental sustainability, with the aim of minimizing e-waste generation and resource consumption. Unlike a traditional linear economy in which products are discarded as waste and there is no effort to keep them in the use cycle, a circular economy aims to keep materials in use as long as possible
[12], ideally indefinitely, through recycling, remanufacturing, refurbishing, reusing, and longer use.
Figure 1 illustrates the basic concept of a circular economy
[13].
Figure 1. An illustration of a circular economy concept.
Recycling involves redirecting materials away from the waste stream and processing them to return them to productive use
[14]. Remanufacturing involves restoring used products, which may be defective, to like-new condition by replacing the damaged parts and then distributing them for use. Refurbishing is similar to remanufacturing but involves a minimal restoration, such as cleaning and testing for slightly used or unused products without significant defects, such as cosmetic issues
[15]. Reusing refers to extending the life of properly functioning products that the original owner no longer needs through reselling or passing them onto others in a secondary market
[16]. Longer use refers to improving durability to postpone disposal.
An ideal circular economy eliminates or minimizes the transfer of natural resources into waste, thus reducing adverse health and environmental impacts and promoting natural resource conservation and economic benefits. The objectives of a circular economy are rooted in sustainability
[17]. A circular economy has been recognized as a means to achieve sustainability, which is the design, production, use, and disposal of the materials used in products in a way that minimizes negative environmental impacts, preserves resources, and promotes long-term social and economic well-being
[17].
One of the main approaches to realizing a circular economy is the longer use of products by increasing their durability. Increasing product durability influences waste generation and resource consumption by extending a product’s life. Although consumers have various reasons for replacing products (e.g., functional failure, dissatisfaction with the appearance, or desire to have the latest version of products), their attitudes toward the circular economy would significantly impact its adoption by their extended use of a product
[18]. The cause of 30% of discarded devices is functional failure, which includes damage, malfunction, or inoperable conditions
[19]. Specifically for smartphones, failure accounts for 40% of the reasons for their disposal
[20]. Thus, improving product durability should reduce the amount of waste generated and decrease the number of replacement products that need to be produced, leading to reduced resource consumption and waste.
Although improving durability enhances circularity and can contribute to sustainability
[21], there are exceptions wherein improving durability may not be sustainable. For example, although plastic bottles and cutlery are durable (i.e., they will not wear out rapidly and can be used many times), they are often discarded after only one use and are difficult to recycle. On the other hand, products such as nondurable cardboard furniture and paper bags are more sustainable because they are made from renewable resources and are easier to recycle. A complete discussion of the complicated relationship between durability and sustainability is beyond the scope of this research. However, despite these limited exceptions, most durable products are more sustainable than nondurable ones and produce less waste, particularly for EEE. In conclusion, embracing circularity leads to improving sustainability, and one of the critical elements of product circularity is the use of more durable products. To quantify and compare durable products, one needs to have measures or indices of durability, which is the main subject of this research.
Finally, it is critical to note that minimizing resource consumption and e-waste within the broader discourse on sustainability requires the consideration and optimization of various product features, including reliability, repairability, and upgradability, as well as the product’s energy efficiency.