Why give a kid a cell phone?
To contact each parent independently. To have an emergency communication system at their fingertips. To be able to be tracked so you can keep an eye on them when they are out alone.
All good reasons.
But once you give a kid a cell phone, a whole new array of problems opens up. Starting with overuse of that device to the detriment of their intellectual and social-emotional development.
I’ve seen a disturbing trend among children of divorce where they use their parent-given cell phone to call the other parent with every problem that arises with the parent they’re with at the moment. Of course kids are going to have complaints and even issues with their parents! That’s normal.
What isn’t normal is turning to the other parent to play good cop-bad cop, or expect the parent to resolve all problems in their lives. Cell phones are making this pretty much the norm.
Kids in the 21st century are not learning to problem-solve like kids from earlier generations, who had open spaces and silence and inevitable face-to-face contact with people who caused them grief.

At a certain point, your kids do need to learn to advocate for themselves and problem-solve, and by constantly being available at the tap of a text or for a quick phone conversation, you’re depriving them of the ability to do so.
Some kids call their parents with every little, tiny thing. Kids of divorced parents are typically pretty independent. We used to be able to manage our small issues when we couldn’t make calls all the time. But with the advent of cell phones, they’re calling parents with everything that crops up.
When a parent tries to take away a kid’s phone, the child might reply, “Well I have to have access to Mom.” Fair enough. Get a land line!

If you’re concerned about the impact of too much screen time (who isn’t?), put their phone in a box and say they can use it to call the other parent but that’s it. You don’t want to get in trouble with the court if your kid claims they wanted to call the other parent but you did not allow it.
At the same time, when your child goes to the other parent, and you ask them to check in, who is that for? Your comfort, or theirs?
If you have a decent relationship with your kids, they’ll get in touch with you – when they want and need to. When they’re with the other parent, let them be with them.
Children of divorce compartmentalize so they can fully be in one place and not always feel disrupted. Let them be where they are.
Every time they are with one parent, they are away from the other parent and they miss them. When you call them a lot, are you making them miss you more?
Plus, calling too much can disrupt the other parent’s time, which is not fair. You can go a day or two without contact with your kid!

Keep in mind, also, that when your child comes to you with a complaint, you are not hearing the whole story. The responsible thing to do would be to call your co-parent and say, “Hey, our child said this – what’s really going on?”
A child might say, “Dad never feeds me – I’m starving!” when the other parent could be in the kitchen making mac and cheese as you speak. Benefit of the doubt goes a long way in co-parenting.
At a certain point, you have to trust your kids to make their own good choices, and if you’re constantly in touch with them, demanding that they call and respond all the time, they’ll never get there.