I wouldn't ride without my phone. Even though there are always houses to stop at, I ride on some "country roads" that are fairly deserted. I would hesitate about stopping someone driving by; I'm not someone who obssesses about "strangers," but I would rather call a friend, child, or spouse to help me if I needed it. This point was driven home to me a few years ago, when my son first started riding. He was crossing a major highway intersection when his cleat came out of the pedal. He crashed and hobbled to the sidewalk. Realizing he couldn't walk well, he was sitting on the curb, when a physician from a nearby hospital was on the way to pick up his daughter from school. He brought my son home. I was furious he had taken a ride with a stranger and that's when we got him a phone.
I hardly use my cell phone compared to most people, since I am a teacher and I can't sit and get calls all day. But when my family has to reach me, it does provide peace of mind.