The first group I play in meets weekly (with rare exceptions) every saturday and starts at 5 pm (some years back we started at 2 pm, but one guy has to work on most saturdays now) and lasts until 2 or 3 am usually, but often also until 5 or 6 am in the morning, rarely even until 8 am. Average would be from 5 pm til 3 am, I guess. That's 10 hours.
The other group I play in meets weekly (with some exceptions) every thursday and starts at 7 pm and lasts until somewhere between 12 pm and 2 am (rarely 3 am). Average would be from 7 pm til 1 am. That's 6 hours, which sometimes seems a little short.
7 hours doesn't really sound all that bad to me.
Back when we had our huge Shadowrun campaign running (with multiple simultaneous groups and a player base of over 30 players, the whole thing was going for 7 years or so) we met monthly at sundays from 11 am til 10 pm!
Bye
Thanee