Well,i think in the weekends there are little more players than the week days,the people are off work have more freetime,and for those who work in the
poker sites the weekends offer better tournaments than in the week days.
I also think that every player has a different schedule.Some play daily,some play only in chosen days and some play by schedule.There is no rule kind of thing for that.Thats my opinion.
Oh,for the "Veteran" players,i think they play a lot more than we can imagine....