Many people believe the universe was created from the Big Bang and there is a lot of evidence to support it. IF you believe in it, at some point the universe will go back to that single point of energy as it collapses back once it finishes expanding. This process should in theory continue forever and there could be an infinite number of universes at any time.
If this is true, each and every one of us should have their entire lives duplicated again an infinite number of times forever. There would be an infinite number of versions of it, since every decision you make changes things, but one of the paths should be a complete repeat of your current life.
I wonder if that means we will be the same person, even if everything around us and every atom is the same when the same universe we live in now starts over again with us in it. Mathematically, their is a near 100% chance that at some point in time whatever created the world we live in now will happen again.
If we did not exist, time would not exist either, so the fact that it could take trillions of years to happen would only seem like an instant. We are here today, but did not exist for billions of years when the universe was first created.