How can variable naming conventions in PHP impact the readability and maintainability of code?

Variable naming conventions in PHP can impact the readability and maintainability of code by making it easier for developers to understand the purpose of each variable. Consistent and descriptive variable names can help other developers quickly grasp the intent of the code, reducing the time needed for debugging or making changes in the future. By following a naming convention, such as using camelCase or snake_case, developers can create a uniform style that enhances the overall readability and organization of the code.

// Example of using camelCase naming convention for variables
$firstName = "John";
$lastName = "Doe";

// Example of using snake_case naming convention for variables
$user_id = 123;
$user_name = "johndoe";