One of the things I notice most moving between wooden and metal planes is the drag on metal planes. Chances are you will not even notice it if you are used to metal but things can be made to move more briskly and therefore less energy wasted. The solution, a candle! No mystery, rub it in and go! Why is a candle a good choice? Excellent value, easy to apply, no mess it is truly a win win! Use it everywhere, too much friction on saws, moulding planes or wooden planes. Save your energy for the task in hand rather than overcoming friction. How many do you need, buy in units of four!