I always have my phone on me.
There was a rumor a couple years ago. It went ... Target would reimburse an employeees $x amount per month to use their phones on the floor to help guests.
That hasn't happened. So, I carry mine with me, but rarely use it. I mainly use it to call other stores either to hold a product for a guest or get info regarding plano or signing.
A funny story: a former STL was very strict regarding cell phone use and personal calls made to the store. This was before she had kids. Then, she had two kids herself. One day, I'm walking past shoes looking for her. I find her there, while the store is open, talking to her kids' preschool. I stood back respectfully waiting, as I would anyone. When she got done, she looked at me sheepishly and said ... It's was important. I thought to myself, really, you couldn't walk off the salesfloor? And oh, all those times you disregarded other people for getting calls at work. Those calls could have been from their kids' schools. Or whatever was important to them.
So, yes, I have my phone with me. If my dad, sister, etc are in an accident, health problems, etc. I am taking that call. But I'll walk offstage to take it.
BTW, that STL was hands down the best I've ever had, especially after she had kids. She's still with the company, just in another district.