# How React Rendering Works and Why Memoization Is Often Not the First Fix

DevFeed: [How React Rendering Works and Why Memoization Is Often Not the First Fix](<https://devfeed.tech/articles/your-usememo-probably-isn-t-doing-anything-18116.md>)

Original publisher: [Read original article](<https://thetshaped.dev/p/react-rendering-demystified-your-usememo-probably-isnt-doing-anything>)

Author: The T-Shaped Dev

Published: 2026-07-28T06:10:09Z

Content type: tutorial

Language: en

Sources: [The T-Shaped Dev](<https://devfeed.tech/sources/the-t-shaped-dev.md>)

Topics: [React](<https://devfeed.tech/topics/react.md>), [ui](<https://devfeed.tech/topics/ui.md>), [Code](<https://devfeed.tech/topics/code.md>), [JavaScript](<https://devfeed.tech/topics/javascript.md>), [Development](<https://devfeed.tech/topics/development.md>)

Tags: [code](<https://devfeed.tech/tags/code.md>), [component](<https://devfeed.tech/tags/component.md>), [context](<https://devfeed.tech/tags/context.md>), [javascript](<https://devfeed.tech/tags/javascript.md>), [react](<https://devfeed.tech/tags/react.md>), [render](<https://devfeed.tech/tags/render.md>), [state](<https://devfeed.tech/tags/state.md>), [ui](<https://devfeed.tech/tags/ui.md>)

## AI overview

This tutorial explains that a React render is a component function call, while DOM updates happen only during the commit phase. It identifies state changes, context changes, and new child elements from a parent as render triggers, and argues that moving state or restructuring children often helps before memoization. It also notes that StrictMode intentionally renders twice in development and that the compiler cannot move component state.

## Source excerpt

One rule explains every React re-render. Get it right and memoization becomes the last fix, not the first.