We got our kids smartphones when they started middle school -- for our convenience, not their entertainment. I control what they install and I set time limits on when they can use them. They are not allowed to have social media accounts, and thus far my only bugbear is the fact that I have to allow browser access but that then allows unfettered access to Youtube.

I generally trust my kids and they're pretty responsible, but there's a lot of stuff out there they could inadvertently wander into, and while they probably aren't at elevated risk, I don't want it to happen sooner than necessary.

They have Android phones, btw, and are practically the only ones in the school who do. The result has been that they use Messages + Telegram for chat. They barely acknowledge the fact that their Google accounts mean they have email accounts, and even if anyone sends them anything they don't read it. App-based push notifications are a requirement if you want tweens'/teens' attention.

We bought them phones as a safety precaution because they 1) ride their bikes to school, and 2) we're all over the place in the evenings with sports practices, some of which don't end until 9:15pm. We appreciate them being accessible -- by us -- and giving them the ability to communicate with us and their friends, too.

Phones are not allowed in bedrooms or bathrooms in our house, either, for adults or kids. :)