Grammarians have no doubt pointed this out before, but the phrase "if and when" (or "when and if") is totally preposterous. "If and when I ever make it to New York, I will definitely go see the Yankees play." Okay, if you go, there is no question of when, because if you don't go, there is no when. There is only a when if you do go. And when you do go, there is no if. You go a certain time and there are no ifs, ands, or buts about it.
And you can't really say "if or when" because that's either redundant or contradictory. It's not an either/or situation. If you go, there will be a when. If you don't go, no when. You could have an intention to go when, but then if you don't go, there is no when. So just say "if." Or "when."
Except that doesn't sound as good as "if and when," does it? The naked if or naked when doesn't quite do justice to the contingent nature of existence on this paradoxical planet. On the quantum level, a particle can appear at two places at once. Or two particles separated in space at a distance farther away than they could reach at the speed of light can still communicate with each other instantaneously. Light can be both a wave and a particle. And so on. Therefore, let us wallow in our indeterminacy and speak the preposterous. When and if we actually do arrive at clarity in terms of who we are and why we're here, our linguistic formulations may magically rearrange themselves anyway so that we babble in algorithms that comprehend all the mysteries of n-dimensional reality.