About half an hour on Sunday mornings and 10~ mins the second session, but I'm slowly making that as close to 0 as possible.
One thing that's helping is Lobsters. Lobsters is super slow so if I do make a full switch from HN to that I only need to check it a handful of times a week.
But to me, it's not so much about how much time I spend on the time but rather the why. I simply don't get as much value out of HN as I think I do. Most news are irrelevant and unimportant, and I haven't really learned anything too insightful like others said they have (sadly). Simply put, tech news boards apparently just aren't for me.
This is why I've stuck with single player games. Aside from a summer where I spent 12 hours a day on Counter Strike, I only play single player games enough to just finish the main story (don't care much about unlockables or anything crazy). I finish them and that's it!
It's not impossible. I went from a hourly checker to only checking it twice a week. You just need to practice self control and realize most tech news aren't interesting or useful to know.