I’ve been wearing contact lenses for more than 10 years now. Switched to contacts from my clunky spectacles when I started my PU(aka 11th). Guess who I am & win! When you use something for 16x7x365 (I won’t say 24×7, since the lenses are off when I’m sleeping), you tend to know it inside out. And especially when it’s something like contact lenses, which sit on your eyeballs, every little change will result in instantaneous result.