My employer sprang for a Blackberry (the company pays for the plan) when my husband died and they were worried i might quit work to raise my kids. Honestly, I get no signal in my houuse, or in my lab/office, and I absolutely turn the thing off while in my car (driving) - so when is anyone going to reach me that way? While I am out shopping?
I do not see how, in such a short time, people became so hopelessly addicted to needing to be constantly in touch after generations of your phone staying at home on the wall. I hope that the pendulum of hysteria swings back to a more neutral position.
There
are times that we do not need to be reachable: when one on one with a personal friend, or while in the bathroom come to mind.
That said, there are times that the convenience is nice. I buy a cheap phone for my kids' trips away from home. Funny thing, they wont talk to me on them, but they wil text like crazy, which reads as a travelog of sorts.

it's also nice to have the cell when my car breaks down or something happens. (try finding a pay phone these days!)