What are the best practices for outputting variables within strings in PHP for readability?

When outputting variables within strings in PHP, it is best practice to use double quotes to allow for variable interpolation. This makes the code more readable and easier to maintain. Additionally, using curly braces around the variable within the string helps to clearly delineate the variable from the surrounding text.

// Example of outputting variables within strings for readability
$name = "John";
$age = 30;

// Using double quotes and curly braces for variable interpolation
echo "My name is {$name} and I am {$age} years old.";