In iOS 9, sending an SMS would pop up a little green progress bar. When that bar disappeared, you knew that the message had been sent. In iOS 10, that bar is no longer present by default and I haven't been able to find a way to bring it back. I live in a weak coverage area and it's fairly common for messages to fail to send, but under 10 I don't know how to tell whether they've succeeded, short of leaving the Messages app open for 20 seconds and checking that the red "!" doesn't appear. Obviously that's not ideal! How can I tell whether an SMS message has finished sending?