Approaches for the estimation of timescales in nonlinear dynamical systems: Timescale separation in enzyme kinetics as a case study

•Biophysical, pairwise balance, and minimum simplification approaches are reviewed.•The Michaelis–Menten reaction is used as case study to introduce techniques.•The commonly used pairwise balances approach may derive non-separated timescales.•A lesser-known, more general inverse rates approach by Rice is revitalized.•Rice’s approach derives timescales identical to the accepted biophysical approach.