There's a common pattern: build the thing, then try to make it fast. By then the slow decisions are baked in, and you're left optimizing around them.
Performance works better as a constraint you accept up front. When 'it must load in under two seconds' is a rule, it changes what you choose: fewer dependencies, lighter media, smarter rendering.
What we budget for
- Largest Contentful Paint under 2.0 seconds.
- Interaction to Next Paint under 150 milliseconds.
- Cumulative Layout Shift under 0.05.
These aren't vanity metrics. They map directly to how fast and stable a page feels, and a page that feels fast converts better than one that merely looks good.
Users don't read your performance report. They feel it in the first second.
Treat speed as a feature from day one and you rarely have to 'fix performance' later. It was never broken.