Using red light at night preserves your eyes’ adaptation to the dark. Use a red colour filter to put your iPhone and all apps into a red night mode, to let you use your phone and preserve your night vision.
I don’t like to delete things, especially not photos. I also shoot in RAW and JPG; I keep the JPG files for quick sharing to my phone, social network posts, etc. Holding down the shutter can very quickly create gigabytes of photos. How do I backup gigabytes of photos safely?