Many say impossible.
But I disagree in two cases, and both are among the strongest pair-splitting cases etched in stone:
Always split Aces.
Always split 8s.
Is my reluctance to always do so based on odds?
It’s based solely on what seems to happen each time I make either of those plays.
If you’ve got a pair of Aces against a dealer’s stiff up-card, then splitting them is of course a no-brainer. But when you’ve got them against a dealer’s up-card of 7,8,9,10 or Ace, you need two successful hits for a chance to win both hands if the dealer already has a made hand, quite difficult when you’re permitted just one card on each split-Ace.
I prefer just hitting Aces with the opportunity to hit again…and again. With each Ace counting as 1 or 11, I like my chances of making a pat hand.
Basic strategy says always split them. I sure as hell don’t like the looks of that when I see the dealer’s up-card is 9, 10, or Ace. If he’s got any ten-value card in the hole, my goose is cooked—twice!
But what the heck do I know?