Hi, my dear sister. First...
My daughter, 11, has a cell phone. We also have a land line. She does talk on the phone, but we don't have a lot of young ladies in our neighborhood, none her age, and so, sometimes, it's a good outlet for her to be able to call on a friend to chat with. In our house, she prefers the land line as she can rest it on her shoulder. It's more comfortable.
When I talk on my cell phone for any period of time, I always get a headache, so I am not a big fan of "hanging on the phone" on the cell phones, but I have found them to be quite handy when I am out.
As to my daughter, she is required to take her cell phone with her to school and when she goes to walk the dogs, or whenever she goes out on her bike, etc. In this day and age, I am most concerned that she have that thing with her in the event something goes on and I need to give her instructions, or whatever. Also, when she is out in my neighborhood, I am not comfortable if I can't call her right away. Alternately, she has called me from the phone to tell me she is changing the plan we made before she left our house. I just feel better when she has it on her person.
My daughter's phone is more for my convenience than hers. Alternately, she has our home phone to call friends on. As a matter of fact, just last Friday I was fussing at my daughter about not carrying her phone to school.