Product lifetime

glass Definitions of product lifetimes vary depending on what aspects those conducting research are interested in. Generally, actual product lifetimes refer to the actual time that a product exists in a particular state. as "the ability of a product to perform its required function over a lengthy period under normal use conditions of use without excessive expenditure on maintenance or repair" (p. 5). In contrast, longevity encompasses more than just the material properties of the product. and Oguchi et al. and to outline several definitions and discuss methods for identifying actual product lifetimes. Murkami et al. identify the following overarching concepts in product lifetime definitions which are discussed below: Age, Residential time, Service life, Possession span and Duration of use. Age A product's age is the time from when the product was created to either the present or "the time of interest" (: 600) for the researchers. Residential time Residential time is considered to be time in which a product, its constituent materials and parts, exists in society. Residential time includes the time in which a product may be broken and/ or discarded. Service life According to Murkami et al., the service life of a product refers to the duration of time for which products continue to work and can be used. Possession span The possession span is the period of time that a user has possession of the product. Duration of use The duration of use indicates how long a user uses the product for. Murkami et al. distinguish duration of use from Service life by noting that duration of use is measured for a specific user, whereas Service life describes the total in-service use of the product for all its users (accounting for transfers of ownership e.g. reuse). Additionally, possession span is distinguished from duration of use, as possession span includes "dead storage" (: 601) time, where a product is owned by a user but not in use (i.e. in storage). == Product lifetime extension ==

Product lifetime extension business models (PLEBM) PLE is enacted through various entities that can be generically denominated as product lifetime extension business models (PLEBM) and which aim at improving product design (nature strategies) or increase the lifetime of the product during post-production phases (nurture strategies). sought to identify and test differences in definitions of product lifetime expectations. Oguchi et al. enquires about "reasonable" expected lifetimes, while Brook Lyndhurst discusses "normal" expected lifetimes. Wieser et al. identified the tension between everyday expectations and desires, distinguishing between these expectations in his study of 21 products. In addition, earlier work by Tasaki et al. and more recent work by WRAP have asked users to report both how long they have owned an item for, and how long they expect to use the item for in future: WRAP term this "active use". Building on these previous studies (described above), Oguchi et al. identified and tested three distinct definitions of expected product lifetimes, these are outlined below. Intended lifetime Oguchi et al. define the intended lifetime as the length of time for which a user intends to use the product in question. Ideal lifetime The ideal length of time for which a user expects their product to last. Oguchi et al. describe this as "the highest preference of consumers". Predicted lifetime The realist prediction by the user of how long a product will last. The user is thought to make this prediction based on their previous experiences and "other relevant factors" (Oguhci et al.). == Measuring product lifetimes ==

Academic enquiry into the product lifetimes of electrical and electronic equipment was undertaken in 2000 by Cooper and Mayers who conducted household interviews and focus groups to establish the age at discard (actual product lifetime) and expected lifetimes for 17 products. Since this study, work has been undertaken by other academics into measuring actual and expected product lifetimes; the methods employed are outlined below. Actual product lifetimes Actual product lifetimes can be measured using a variety of methods which include: product testing, discard surveys, user interviews and modelling. These are discussed below. Product testing Products can be tested under laboratory conditions to assess their lifetime under different conditions of use. One of the earliest attempts to estimate product lifetimes was undertaken by Pennock and Jaeger who utilised actuarial methods to measure the Service life of household goods for one owner. In the 1990s, Bayus modelled car replacement rates and Bayus and Gupta evaluated the user decision-making process and factors around replacement car purchases. interviews. These studies asked individual participants to report their expectations for product lifetimes in units of time. Survey methods (such as Oguchi et al.) can also use Likert items to evaluate if current products meet users expectations with regard to durability and longevity. Focus groups Focus groups can be convened where participants take part in discussions to reach a group consensus on product lifetime expectations. ==See also==