From our training trip we realised that it would be very useful to have a rearview mirror. When travelling together with another person you can check the mirror to see if they are still behind you rather than turning your head. Recently I was driving ahead of Matt and he slipped and fell of off his bike. I only realised a few hundred meters down the road that Matt wasn’t behind me, luckily he fell into deep grass and he wasn´t hurt.
But also when driving on busy roads a rearview mirror can be very useful and help you to be aware of cars or lorries coming fast from behind. Especially when tuning off the road a rear view mirror can be very helpful as you don’t have to turn around when looking back to see if you can go off the road. When riding recently I looked back to turn off a road and all of a sudden I realised that I was nearly driving into the curb, so they should also help to prevent accidents.