Apple allows you to check how much time you actually spent on your iPhone any day. It'll breakdown the average time you spent each day over the course of a week, it can show you what apps you used the most and at what times each day.
Two weeks ago I opened this and started looking at my numbers:
I averaged 6hr 14min on my phone each day.
Picked up the phone 92 times a day.
Received 124 notifications each day.
For me, I would have never believed I used the phone that much if I didn't have the data.
Step one was removing all the top time-sucking apps that I didn't need.
I got rid of Twitter, Reddit, twitch, all the games, and all social media aside from Instagram and YouTube because I test my videos on my phone via YouTube and Instagram's website stinks out loud.
I checked my numbers today for the first time since removing all that stuff and making a conscious effort to not use my phone as much, and the daily average is down to 2hr 18min.
Still not as good as I want, but I do read books on my little iPhone screen, I listen to podcasts while I workout, and catch up on YouTube while I'm running the treadmill, so I know that at least an hour of that screen time each day is not time that I'm wasting or avoiding work.
Now to snip away as much of that remaining hour. I'm hoping to get the usage down to around 90 minutes a day including all the reading and workout accompaniment.