I got a S4 for a family member, but didn't get AppleCare+ because I've decided it's not worth it anymore for my Apple products, even for my iPhone (which is my most used Apple device). On further reflection, it probably does make sense for this Watch. I understand that you can add it online if you have the Watch's serial number (which I have), and there are some diagnostics run remotely, but do you physically need to have the watch in your hand? Or is it enough that the Watch is on and paired to an iPhone? Many thanks in advance.