Three myths about performance budgets

This is cheap to get right at the start and expensive to retrofit. A few things about performance budgets that get repeated more often than they get checked.

Real-world numbers from actual visitors matter more than a score produced on a fast laptop. It rarely shows up as a line item, which is exactly why it slips.

“It only matters for big sites”

A number in writing stops slow creep. There is a version of this that is over-engineered, and it is worth avoiding. Anything you cannot measure here, you are deciding by taste, which is fine as long as everyone knows it.

“We can deal with it after launch”

Sometimes true, usually expensive. There is a version of this that is over-engineered, and it is worth avoiding.

“Our platform handles it”

Enforce it automatically or it gets ignored. Small and consistent beats large and occasional here. The version that survives contact with a real deadline is the simple one.

How to tell if yours is fine

Speed is a feature people notice only in its absence, and then they leave rather than complain. Three things worth confirming about performance budgets before you move on:

• Someone can say what the current setup is without going to look
• A number in writing stops slow creep — and you know whether that is true here
• There is a way to tell whether the last change to this helped

The point is not perfection, it is knowing which of these you have consciously chosen to skip.