Hi Barbara! When senators and members of the House of Representatives meet in Parliament House, the sittings last for an average of 11 hours a day. Sometimes daily sittings go for much longer, with senators and members meeting long into the night!
Before the beginning of each year and after a federal election, a sitting calendar is distributed to let everyone know when Parliament will be sitting. There are on average 18 to 20 sitting weeks a year. Sittings are usually held Monday to Thursday in 1 or 2 week blocks.
Each parliament is the length of a House of Representatives term, which is 3 years or earlier if an election is called.