What are the best practices for handling timestamps and date values in PHP to avoid errors like getting the same timestamp for different dates?

When working with timestamps and date values in PHP, it's important to ensure that the timezone is set correctly to avoid errors like getting the same timestamp for different dates. One way to handle this is by explicitly setting the timezone using the `date_default_timezone_set()` function to the desired timezone before working with timestamps and dates.

// Set the timezone to the desired value
date_default_timezone_set('America/New_York');

// Get the current timestamp
$timestamp = time();

// Convert timestamp to a date string
$date = date('Y-m-d H:i:s', $timestamp);

echo $date;