Depends on your kids, really. Our eldest was a little more "adventurous" about misuse of the phone. We took it for 2 weeks. After that we really didn't have any issues, and we didn't set hard and fast rules after he was a junior in high school. Prior, the phones were left in the kitchen when they went to bed. We had no set bed time, but before they went, the phones went in the kitchen.
Both kids were fairly early to bed types by high school. The rules have been mostly simple stuff. Find my Phone stays enabled. Period. We have the option to look at (or take) the phone at any time at are discretion since it is ours, and we pay for it. You will keep it in the case provided (if you have an issue with the case, we'll discuss, but generally, they stay in Otterbox defender cases, and we have never had a phone broken or screen cracked on one). They are not used at the dinner table (whether at home or restaurant), unless there is a specific reason (sometimes in the course of conversation while waiting in restaurants either for the food, or the check, we would be stumped on what year a movie was released, or who sang such and such song, and someone in the group would google the answer... but it was part of a group conversation, not someone isolating themselves looking at the phone).
No use while driving. No using during school against school rules. It's a communication tool WE are providing for you to communicate with US. So you will. Text when you arrive at your destination, and when you leave to come home. Text with changes in plans. Respond to my texts (if you aren't driving, etc).
You will not post inappropriate pictures. I will have access to all your accounts. And you will friend me on your social accounts. (These last ones mostly for our daughter, as our son is grown and adulting now and getting his own phone account, too. But once he turned 18, everything was a courtesy, not a requirement with him, and he became very courteous.)
They both have ended up using phones as their alarm clocks. I didn't get it, until I started using my own as my alarm clock. It works very well, is easy to change (unlike most night stand type alarms), the time is always accurate, and you can adjust the volume or sound to whatever works best for you. So the "not in the bedroom" and "turn it in before bed" rules stopped applying. Our youngest is on her phone a lot, but doesn't stay up on it all hours. She is a good student, and grades and such are high priorities to her. She doesn't do anything to jeopardize her performance at school. She gets up on her own, drives herself, and sets her own bedtime (which is rarely very late, and if it is it's a weekend, or Thursday when she doesn't have dual enrollment classes, so doesn't report to school until 10:45 am).
Kids who push and test limits, need more defined limits. Kids who try to do the right thing need more guidance than hard and fast rules. Either way, they need a little space to make mistakes, b/c eventually they won't have you making those rules and they need to learn self discipline regarding device use, just like everything else.