How can PHP developers effectively check if a variable is empty before outputting content?

To effectively check if a variable is empty before outputting content, PHP developers can use the `empty()` function or a combination of `isset()` and `!empty()` functions. This helps prevent displaying empty or undefined content on the webpage, improving the user experience and preventing potential errors.

// Using the empty() function
if (!empty($variable)) {
    echo $variable;
}

// Using isset() and !empty() functions
if (isset($variable) && !empty($variable)) {
    echo $variable;
}