This technical note examines the applicability and limits of temporal concepts in extreme cosmological regimes, with a focus on nucleation zones such as the Big Bang, cosmological bounces, and phase transitions. Rather than proposing new physical models or modifying established dynamics, the work introduces a methodological diagnostic based on operational clockability: the availability of physically meaningful clocks required to interpret a global time parameter. The central claim is that, in certain early or extreme regimes, the absence of clockability restricts interpretation, not calculation. The analysis distinguishes between non-clockable, relational, and dynamically stable thermodynamic regimes, and provides a structured checklist to assess when temporal extrapolations constitute a domain error rather than a physical prediction. A qualitative diagram is included to illustrate the stratification of temporal regimes without introducing new ontological assumptions. This contribution is intended as a methodological clarification within contemporary cosmology and foundations of physics, offering epistemic hygiene for the interpretation of time in frontier regimes. It does not advocate new physics, but delineates the domain of validity of existing temporal concepts.