Are Gillette and Schick, which account for about 90% of the replacement-blade market, making sure razors that don't last more than a week to keep replacement revenue going? Consider that an eight-pack of Gillette Mach3 Turbo shaving cartridges runs $24 at Walgreens. With a once-per-week cartridge change that's $156 each year on razor blades. Jeff Grant, president of Coating Services Group, a Lakeside, Calif.-based company that makes scalpels for medical use says companies could make a ceramic blade that maybe costs $100 and lasts for years, notes columnist David Lazarus.