useCallback Hook - WHY ?

[arvish-codal]

Functionality : -

• Display simple text.
• A component to display age & increment age.
• A component to display salary & increment salary.

WE MIGHT BE THINKING WHY do we need to break this down into 5 components ? Could we not just
have all the JSX in the parent component itself and make it simpler.

We definitely could do that but we've written the code in this particular way because we need
to understand about performance optimisation & off-course the useCallback Hook.