Edited sentence: Back in the good old days, one had to shave with a blue blade - often from Gilette.It wasn't long before all other shaving blade manufacturers had to follow suit.The first shave was great, the second OK but the third a real horror.Then Wilkinson Sword introduced the  stainless steel  blade.This development ranks with the Japanese manufacture of decent cars forcing the American Car Manufacturers to up their game.With a little care a single double edged blade would last for weeks