we must do this again sometime

Richard's life changed in a moment. That's how he tells it, anyway.
For a while, he was starting to get hung up, bad. His life had changed, but the first few months were spent pondering the countless if-onlys that had led to the change, and without even the least of which, he would never be where he is now. Pondering the if-onlys. For months, which is a bit of a stretch no matter how you cut it.
He could feasably have kept pondering them for the rest of his life. But he didn't. That's another bunch of if-onlys right there.
It doesn't take long to realize why he says his life changed in a moment and just leaves it at that.