I read many people throw out their de blade after maybe 2-10 shaves on average, right? That is reached its lifespan. So how come all the cartridge blades like gillette makes say it lasts up to 25 shaves? Are we throwing out de blades way too soon? Or is gillette's definition of lifespan grossly exaggerated by them? Or are those cartridge blades substantially and materially different? Or the fact there's 3-5 blades per cartridge make any difference? Thank you.