Natural phenomena which exhibit discrete self-similarity are under consideration. Earlier, self-similarity of some non-smooth phenomena was studied using the concept of log-periodicity, however there was a gap in this field. Recently it was attempted to fill this gap by concentrating on the study of a new concept of parametric-homogeneity (PH) based on the use of discrete group of coordinate dilations. It is argued that parametric-homogeneity can be helpful in the modelling of self-similar non-smooth phenomena. Some models of natural phenomena which have PH-features are presented and some properties of PH-functions are discussed. As an example of practical usage of these functions, the phenomenon of seismic activation prior to a major earthquake is considered.