How can developers troubleshoot issues with cookies in PHP, such as incorrect expiration times?

To troubleshoot issues with cookies in PHP, such as incorrect expiration times, developers can check if the expiration time is set correctly in the `setcookie()` function. They should ensure that the expiration time is calculated accurately based on the current time and the desired duration. Additionally, developers can use `var_dump($_COOKIE)` to debug and see the values of cookies being set.

// Set cookie with correct expiration time
$cookie_name = "user";
$cookie_value = "John Doe";
$expiration_time = time() + 3600; // expires in 1 hour
setcookie($cookie_name, $cookie_value, $expiration_time, "/");

// Debug cookies
var_dump($_COOKIE);