Last year I have flown 944 hrs Blocktime on 737-400/800 for Air Berlin. I did work on 162 days, so average flight time per day is around 5,8 hrs.
On the other hand, I had lots of Standby-duties and more of these crazy "Available". If you have not been called for duties (flight or stby) the day before until 10 pm, you got OFF.
Happy landings !