Lifecycle thinking is a concept that is used to express a holistic perspective on conventional and extended products, such as Product-Service Systems and Cyber-Physical Systems. Many authors of academic literature make use of this concept by defining or reusing product lifecycle models. Those models express how products are designed, produced, delivered, used, maintained and finally recycled or disposed of. The goal of this paper is to describe differences between lifecycle models, in order to clarify how heterogeneous the models are. A selection of 71 visual models was extracted from literature and analysed. The analysis addresses the preferences in modelling based on paper context, geometric topology of models, and the number of lifecycles contained in a single representation of the product lifecycle. The outlook of this paper suggests topics for future research, such as covering multiple lifecycles at once and discussing whether lifecycle models should be expressed with a common language.