Hmm - I feel I ought to like and approve of mirrors. I've fitted them to the tandem. But instead, I hate them.
- They vibrate (ime) - and take longer to interpret than a quick look behind; it's daft to have a safety feature that requires physical confirmation.
- Their field of view is either so narrow they're useless ........... or so wide they're useless.

- And they're like mirrors on articulated trucks - the slightest move of the handlebars creates huge blind spots.
I prefer relying on looking behind. Frequently.
Aye, and I recognise the dangers of that horrible situation where some tw@t is tailgating. I know I'm looking behind more than I'm looking ahead, and that imbalance of concentration is just so scary and dangerous. I have not yet managed to school myself out of that.