How can PHP developers ensure proper error handling and debugging when working with complex date calculations like determining the difference between two dates?

When working with complex date calculations in PHP, developers can ensure proper error handling and debugging by using built-in functions like `strtotime()` to convert dates into Unix timestamps for easier comparison. Additionally, they can use `date_diff()` to calculate the difference between two dates and handle any potential errors or exceptions that may arise during the calculation.

$date1 = "2022-01-01";
$date2 = "2022-01-10";

$timestamp1 = strtotime($date1);
$timestamp2 = strtotime($date2);

if ($timestamp1 === false || $timestamp2 === false) {
    echo "Error converting dates to timestamps";
} else {
    $diff = date_diff(date_create($date1), date_create($date2));
    echo "The difference between the two dates is " . $diff->format("%a days");
}