Testing Knife Sharpness

What's the best way to determine when your knife needs sharpening?

The tomato test - Sketchplanations

Quantifying Sharpness, Measuring Results - Keith Nix Knives

Testing the Sharpness of Shun Classic Knives Using the Paper Test

5 Classic Ways to Test Blade Sharpness - Knife Life

Razor Blade Sharpness Testing – Refined Shave

Knife descriptions and codes with statistics from the blade

Edge On Up BESS Certified Knife Sharpness Tester

How to tell if your knives are dull - Norfolk Sharpening

Knife Technical Testing - How It's Done - TACTICAL REVIEWS

How We Test Manual Knife Sharpeners - Maximum Sharpness