The first time someone has a new experience, they have no real notion of it, no category by which to sort or compare those experiences, their brain simply remembers it.
The second time someone has a new experience, it is familiar because of the previous experience, but that’s it. It’s not sorted, just connected.
The third time someone has a specific experience, it’s not just familiar, but the feeling of familiarity … is also familiar. This is typically when someone actually constructs a category for associating all those similar experiences; a filter or list of criteria by which to sort specific experiences into that box.
The fourth time someone experiences something, or the first time after they’ve constructed a category, the experience confirms the category – the idea – and thus they can now, finally, actually think about it.
Four is clearly a minimum.
In my experience, they can’t have all four with the same person or it doesn’t work.