The nature of charge transport in strange metals, characterized by linear-in-temperature resistivity (LITR), challenges the conventional Fermi liquid paradigm. A central concept in this field is Planckian dissipation, which posits a universal scattering rate ħ/τ = αkBT with α ∼ 1. However, the extraction of α from resistivity measurements is fraught with assumptions about effective mass and carrier density, leading to significant controversy regarding the universality and validity of this bound. We present a comprehensive investigation across three major cuprate families—La2−xSrxCuO4 (LSCO), Y Ba2Cu3O7−δ (YBCO), and Bi2Sr2CaCu2O8+δ (Bi-2212)—by directly comparing α values obtained from three distinct experimental techniques: dc resistivity (ρ(T)), angle-resolved photoemission spectroscopy (ARPES), and optical conductivity. Our analysis reveals that for underdoped, optimally doped, and overdoped regimes, the α values extracted from ARPES and low-frequency optical conductivity consistently fall within the Planckian limit of 1 ± 0.5, confirming the robustness of Planckian dissipation across a broad doping range. Crucially, we demonstrate that while low-frequency optical conductivity and ρ(T ) analyses yield consistent α values, high-frequency optical measurements show significant deviations. This frequency-dependent behavior resolves a key controversy by identifying the limits of the Drude model in non-Fermi-liquid systems, showing that Fermi-liquid-like formulas remain applicable for extracting Planckian bounds only in the low-frequency regime. Our findings validate Planckian dissipation as a fundamental organizing principle of strange metallicity and clarify the experimental conditions under which it can be reliably quantified.