People I care are usually one of the reasons, I forget about excessively using media. So, they don't suffer from it.
"..how often it squeezes out other worthwhile and important uses of my time"
Theoretically? More often than not!
Practically, as I have ADHD it's not easy to define worthwhile consistently.
"..that I keep justifications at the ready and think about others who do the same"
Usually, I don't think explicitly about it. I don't justify it, I just do it for a while (more or less excessively) and when I deem other task more worthwhile (for whatever reason), I forget about them completely.
I would do (and have done) genealogy for that kind of time. I think I can best describe it as overlap between it and addiction behavior. I base it on:
..how people close to me feel about it
..how often it squeezes out other worthwhile and important uses of my time
..that I keep justifications at the ready and think about others who do the same
I have no declaration to make about it other than I need to be mindful.