Why do I have to wear retainers 24/7 after my braces come off?

Your teeth have been moved around for quite some time.  Now that your braces are off we need to keep your teeth in their new wonderful position!  Wearing your retainers all the time builds your bone strong and healthy so that your teeth stay in this new position.  Kind of like having a broken bone and wearing a cast so that your bone heals correctly.