What does “healthy phone use” actually mean?

I’m launching Dayprint soon, and one question has been on my mind:

Is healthy phone use really about spending fewer hours on the phone, or is it more about understanding the patterns behind those hours?

For example, four hours of intentional use can feel fine, while 40 tiny automatic checks can make the whole day feel fragmented.

Curious how others think about this: when you look at your own phone habits, what feels more important — total screen time, or the way your attention gets pulled throughout the day?