This review explores whether endometriosis is a progressive disease by examining the natural history of lesions through the lens of repeated tissue injury and repair (ReTIAR). Traditional staging systems often fail to predict disease outcomes because they rely on lesion size or volume, which are unreliable markers due to the body’s intrinsic tissue remodeling and fibrotic constraints. Instead, the authors argue that lesional fibrosis and stiffness serve as more accurate indicators of a lesion’s biological age and developmental stage. This progression is influenced by aggravating factors like menstrual cycles and stress, as well as mitigating factors like hormonal treatment or menopause. Ultimately, the text proposes using elastography to noninvasively measure stiffness, which could improve diagnostic accuracy and help clinicians tailor personalized treatments. This framework suggests that while the disease is inherently dynamic, the degree of scarring is the most critical metric for assessing its severity and prognosis.