What should I do if hair color fades quickly, and how should hair salons explain this to clients?

After doing hair color for a long time, the biggest issue is when a client wants a look from a photo, but their base color and hair quality can't support it. I used to try to explain with technical jargon, but clients wouldn't listen. Now, I first use a small hair swatch to demonstrate the fading levels, and then show them photos of the color shades I can actually achieve. By promising less, I…