Lagrangian and Hamiltonian mechanics were useful early on, though. They make perturbative calculations much easier in classical mechanics. If you want to analy

Lagrangian and Hamiltonian mechanics were useful early on, though. They make perturbative calculations much easier in classical mechanics. If you want to analyze the effect of one planet on the time evolution of another planet's orbital parameters, Hamiltonian mechanics is the formalism to work in.