Degradation of bleach

The study consists of studying the degradation of the chlorometric degree of bleach by the influence of several physico-chemical factors as a function of time: - Temperature; - Concentration; - Light; - Metals. According to this study, we found that metals have a greater influence on the degree of bleach than the other factors. Marketed bleach generally has a shelf life of no more than 12 months, which begs the following question: Why does bleach have a short shelf life? And as long as we're asking this kind of question, the answer must be in the form of logical reasons. In our case, the reasons are factors that influence the degradation of bleach, which affects its shelf life. So what factors influence the degradation of bleach extract? And why do they do this?