Imagine the following scenario:
1) User comes to a site
2) User adds 5 products to their cart on the site:
session_start();
$_SESSION['cart'] = array(1,4,7,12,20);
3) User closes the lid of their laptop and puts the PC to sleep
4) 8 hours pass
5) User moves to another location, another internet connection, another IP
6) User opens the lid of their laptop, resuming the browser
7) The products are still in the cart
How do we achieve that the step 7 can/will happen?