[AZ Traveler]

Assuming you have GPS in your phone, I might go with the backup camera first. I like the camera not so much for backing but to see who may be following me closely going down the road. Neither are absolute necessities. The phrase we used when I flew aircraft was "live by the GPS - die by the GPS" - not so much because they didn't work but many folks planned less when using GPS. Agree with the comments that a spotter is still good even if you have a camera.