I don't think having the phone closer is a way to mitigate risk. I've often been many many many hundred feet up the side of a cliff without a phone. In fact I Ieave it home as much as possible.
Knowing your gear and how to use it, and not getting lazy and complacent is what needs to be done. I literally inspect my rock/ice climbing ropes two fingers squeezing at a time there entire 60 meter after EVERY day of use. There was a time that could be upwards of 100+ times a year. If something feels even slightly off, the rope is retired.
How many people throughly inspect your rope systems after EVERY use? Fraying...retired..flat-footed, retired...slight burn mark...retired. biner gate is slow to close, retire....