We solve a recently derived kinetic equation for a dilute quantum system at arbitrary degeneracy and polarization, M. From this equation we develop a spin hydrodynamic equation that allows the generalization of the treatment of spin waves and the Leggett-Rice effect to polarized degenerate Fermi gases. We find a transverse spin-diffusion collision time τ⊥ that is often shorter than the corresponding longitudinal collision time τ∥ that is often shorter than the corresponding longitudinal collision time t⊥. As T→0, τ∥ approaches T-independent value, in constrast to τ⊥∼1/T2. Spin waves would thus continue to be damped even to T=0 K.