What best practices should be followed when defining variables like $timestamp in PHP?

When defining variables like $timestamp in PHP, it is best practice to initialize them with a specific value or function that accurately represents the intended use of the variable. This helps to avoid potential errors or confusion later on in the code. One common approach is to use the time() function to assign the current Unix timestamp to the variable $timestamp.

// Initialize $timestamp variable with current Unix timestamp
$timestamp = time();