Stop obsessing over 100/100 Lighthouse scores. Focus on this instead.

The Lighthouse illusion

Lighthouse runs in a simulated environment. It throttles CPU and network speeds based on standardized profiles. But real users don't live in simulations. They are on patchy 4G networks in moving trains, or using older budget smartphones with slow Javascript execution engines.

If your site gets a 100 Lighthouse score but takes 4 seconds of blank white screen before showing the first paint (FCP), your users are still going to bounce.

What to focus on instead

Rather than obsessing over the score badge, focus on these user centric metrics:

1. Largest Contentful Paint (LCP): How fast does the main hero image or headline load? If the user sees content instantly, they perceive the site as fast, even if background analytics scripts are still loading.

2. Cumulative Layout Shift (CLS): Does the page jump around when images or custom fonts load? There is nothing more frustrating than trying to click a button, only for a layout shift to move it, causing you to click an ad instead.

3. First Input Delay (FID) / Interaction to Next Paint (INP): When a user clicks a menu link, does it respond instantly? Delay here makes a site feel sluggish and broken.

The Sanmora Performance Checklist

Here is the practical checklist we use for our builds:

Always set explicit width and height dimensions on images to prevent layout shifts.

Prioritize hero images using the priority attribute in Next.js.

Limit custom web fonts. Fetching 5 different weights of a custom font can delay text rendering by seconds.

Stop optimizing for Google's algorithms and start optimizing for human patience. Your conversions will thank you.