Dissipative Kerr-cavity temporal Solitons (DKS) are self-localized light pulses that can be excited in coherently-driven nonlinear optical resonators [1], enabling compact, coherent optical Kerr Frequency Combs (KFC) generation, which have numerous potential applications. Numerical studies based on the Lugiato-Lefever Equation (LLE) predicted that DKS can undergo breathing, i.e. periodic variations in their duration and amplitude [2], resulting from a Hopf bifurcation [3]. It was first demonstrated in fiber cavities [3] and recently in microresonators [4, 5]. Here, we address a variety of open questions regarding breathing conditions, dynamics, and properties, in two distinct microresonator platforms: crystalhne MgF2 WGMR and photonic-chip Si 3 N 4 microring.