Simon Singh, the author of The Big Bang: The Origin of the Universe has produced mathematical calculations suggesting that scientists might be able to uncover actual evidence for a big bang before the one that produced the universe we now live in.
If Singh is right, the laws of physics in the previous universe are the same as the laws of physics in our own universe today. Also if they are right, our own universe will eventually contract, and another big bang will produce another universe, and so on, possibly forever.
But although subsequent universes may all obey the same laws of physics, they are not carbon copies of each other.
In other words, what has happened before is not determined to happen again. In that sense, the events occurring during the time of each universe are unique. We are unique. This time will never come again.