I think I study around 22-25 hours a week, on top of my 9 hours of lectures and seminars. This is probably a lot of outside studying, but most of my courses require you to read 70-80 pages a week, and well, I'm a slow reader. And I obviously put in extra hours when I have essays to write during term time, as the above is only for keeping up with the weekly content... so I'm probably closer to like 30 hours a week + 9 hours of seminars.
It definitely feels like a bit too much, as I work 10 hours a week and volunteer another 7 or 8, but I really want to get into a super competitive masters, and I'm not clever enough to effortlessly pull a first, lol.