Performance Budgets in the Real World

Everyone agrees web performance matters. Few organizations actually maintain it. Here's our approach to performance budgets that survive contact with reality.

Beyond Lighthouse Scores

Lighthouse is a tool, not a target. A perfect 100 means nothing if your actual users on actual devices have a poor experience.

We track:

• **Core Web Vitals on real traffic** (via CrUX data or RUM)
• **Time to Interactive on target devices** (not just the latest MacBook Pro)
• **Total page weight by resource type** (identifying what's growing)
• **Third-party script impact** (often the real culprit)

Setting Realistic Budgets

We start with competitor analysis. If the market leader loads in 3 seconds and you're at 8, you have a problem. If everyone's at 8, faster is competitive advantage.

Typical budgets for marketing sites:

• **LCP**: < 2.5s on 4G connection
• **Total page weight**: < 1MB (ideally < 500KB)
• **JavaScript**: < 200KB gzipped
• **Third-party scripts**: < 100KB total

For web applications, we adjust based on complexity—but we still set limits.

Enforcement That Works

Budgets without enforcement are wishes. We implement:

Build-Time Checks

Our CI pipelines fail if bundle sizes exceed limits. No exceptions without explicit approval and documented justification.

# In CI
if [ $(stat -f%z build/main.js) -gt 200000 ]; then
  echo "Bundle size exceeded. Current: $(stat -f%z build/main.js)"
  exit 1
fi

Performance Dashboards

We set up monitoring from day one. SpeedCurve or similar tools track real user metrics. Alerts fire when budgets are breached.

Regular Audits

Monthly performance reviews are part of maintenance contracts. We catch slow degradation before it becomes a crisis.

Common Budget Busters

In our experience, performance problems come from:

• **Unoptimized images** (40% of cases) - Next.js Image helps but doesn't solve everything
• **Third-party scripts** (30%) - Marketing tools, chat widgets, analytics
• **Large client-side frameworks** (15%) - Loading React for a content page
• **Web fonts** (10%) - Three weights of four fonts
• **Unintentional dependencies** (5%) - That one import that bundles 500KB

The Maintenance Reality

Performance isn't a launch milestone—it's ongoing work. Every new feature, every marketing request, every "just add this tracking pixel" chips away at performance.

Build the culture from the start. Make performance visible. Celebrate speed improvements. Make regressions painful to ship.

The sites that stay fast are the ones where someone cares enough to keep them fast.