Speed is a revenue feature, not a vanity metric
Across eleven commerce and lead-generation projects we measured last year, every 500ms shaved off largest contentful paint moved conversion between 3% and 9%. That is not a rounding error — on a store doing ₹40 lakh a month it is a second salary line.
The trap is treating performance as a Lighthouse score to chase. A 100 in the lab means nothing if your real users are on a mid-range Android over a congested 4G tower at 8pm.
Fix images before you touch JavaScript
In eight of eleven audits, images were the single largest payload. Modern formats, correct intrinsic sizing, lazy loading below the fold and an actual CDN typically cut total page weight by 55–70% in under a day of work.
Only after that does bundle splitting earn its keep. Shipping 400KB less JavaScript matters, but it rarely beats not shipping a 2MB hero photograph.
Measure in the field, decide with money
Install real-user monitoring on day one and segment by device class and connection. Then tie each metric to a business number: add-to-cart rate, form starts, booking completions.
When performance work is expressed as revenue rather than milliseconds, it stops competing with feature work for priority — it becomes feature work.