# A Review on the Lifecycle Strategies Enhancing Remanufacturing
## 3 Strategies Enhancing Remanufacturing
### Predetermined Remanufacturing Timing  
The remanufacturing timing of an EoL product is very crucial because, if the product stays in service for too long in its MoL stage, it may be impossible to remanufact that product. This is where the notion of predetermined remanufacturing timing comes into play. As seen in Figure 3 above, this strategy has seen the greatest rise in the number of relevant publications, from 0 papers in the period 1995-2000 to 17 papers in the period 2016-2021. This just shows the importance of this strategy in the lifecycle of a product. It is normally difficult to determine when a product has reached its end-of-life stage just by observing, and there are certain factors that have to be analyzed before decisions can be made.  
Industrial research carried out by [77; 78] has shown that a high percentage of waste products cannot be remanufactured and thereby have to be recycled as industrial solid waste. Considering the product lifecycle, these EoL products cannot be used as the cores for remanufacturing processes. Such a situation can be remedied by using predetermined timing, which consists of evaluating the operating performance of a product such that it does not get to a stage where the product can no longer be remanufactured.  
Remanufacturing is often offered to customers as a restoring procedure with improved performance and reduced total cost [38]. Therefore, remanufacturing should be seen as a maintenance option which should be considered in time when product performance degrades. Product performance degrades with a small ratio at first and a higher ratio after a certain time. This is because the performance of a brand new product is at its peak at the beginning of use and with time the key components start degrading, leading to faster overall product degradation [79]. When product performance is too low to meet the operating requirements, the entire product is wasted at its end-of-life. Product performance is expressed as a decreasing function of operating time [80].  
There are three factors considered in decision making regarding remanufacturing timing, namely economic, environmental and technical aspects [81]. Component performances are taken into consideration when dealing with remanufacturing timing; the main options are:  
1. _Variable performance of key components_: A product is made up of various components and some components are considered \"key components\" due to their importance. Therefore, their performance is observed during their lifecycles so as to determine the exact period it needs to be remanufactured.
2. _Remanufacturing timing with key components_: Given that the structural failure of each component is totally different according to the individual operation environment, identifying the influence on product performance from each key component is important. Moreover, the components are the main cores to be disassembled, inspected and restored. The utilization values in the use phase and the costs in the remanufacturing phase of different key components should not be similar. Accordingly, the specific remanufacturing timing of individual components should be analyzed as the foundation of a product's remanufacturing timing.  
Methods to estimate the performances of these products mainly involve online monitoring for structure failure with the use of sensors or related methods [40; 82; 83].