Take typical hold'em players and sit them down in a limit Omaha hi/lo game for the first time, and their initial reaction will most likely be to marvel that they are dealt four cards, instead of two. With so many starting cards, it quickly becomes easy for such a player to find a reason to play just about any hand. Several hours later, absent incredible luck in connecting with the board, they will leave the table several buy-ins lighter in the wallet, not quite sure what went wrong.
While it's true that players in Omaha are dealt twice as many cards as players in hold'em, it's not true that they have twice as many hand possibilities. They actually have six times as many hand possibilities! An example should make this readily apparent: if a player is dealt , he can make the following two-card hands: , , , , and . The four cards in his hand combine to make six different possible two-card combinations — and since Omaha requires players to use exactly three cards on the board and exactly two cards from their hand in order to make a five-card hand, thinking about a starting hand in terms of its two-card units is not merely an academic exercise.
The ideal starting hand in Omaha has all four cards working together in some way. Very often players are dealt hands in which one of the four cards doesn't really work with the other three in any meaningful way. For example, a player might be dealt . Absent a miraculous board, the doesn't add any value to this hand; it's as if this player is only playing with three cards. Those oddball cards that don't work with the rest of the hand are called "danglers", and playing hands with danglers can wind up costing the player a significant amount of money over a long session.
Why are danglers such a problem? Isn't playing with three cards sufficient? Of course not — not if your opponents are all playing with four cards. But there's a bigger, more mathematical reason why hands with danglers should be avoided. By effectively playing with only three cards, a player does not reduce the number of (meaningful) two-card hands he can make by twenty-five percent; he reduces them by fifty percent. In the example above, by ignoring the seven of diamonds, the only two-card combinations that are possible are , , and . That's three combinations, instead of the six that are afforded when playing four cards that interact with each other in meaningful ways.
Of course, like everything else in poker, there's no blanket rule that should be followed which says that "All hands with danglers must be folded before the flop." Poker is a situational game, and situations repeatedly arise where playing danglers may make sense. Obviously, in a H.O.R.S.E. tournament, a player has a finite amount of time to accumulate chips. His stack size relative to the blinds may dictate taking a few chances by playing danglers (if he's a short stack) or attempting to punish the short stacks by aggressively playing lots of pots (if he's a big stack).
Even in a cash game, there are times when playing danglers may not be the worst decision. Sometimes the three other cards in a player's hand have enough value on their own to make the decision to play correct. A hand like , for example, has enough two-way value in its ability to make the nut low (with counterfeit protection), a wheel straight, and the nut flush that it can be profitably played. Contrast that starting hand with the example given above, . The seven does not add anything meaningful to this hand except an emergency low that will only be good if no other player is gunning for low, while the three other cards in the hand have some high-card value and the ability to make a few Broadway straights and not much else.
Even when a dangler improves a player's hand, it usually only does so in a very marginal way. If the in the above example were the , it would give the player the nut heart draw. Since generally speaking, players should be drawing to the nuts after the flop (especially in a game where three or more players are routinely going to the flop), having a nut draw is useful. But the would not contribute anything else of value to the hand, making it a very close decision whether to play or fold before the flop.
At the end of the day, even despite the situational parameters of any given hand, Omaha players should be folding hands with danglers more frequently than playing them. A hand with three good starting cards may look tempting — after all, it makes three times as many playable hands as two good cards do in hold'em. Just remember what such a hand gives up by not having an additional fourth good card — a whopping fifty percent of the hand's possible playable two-card combinations. Poker players needlessly handicap themselves all the time. This is one handicap that's easy to avoid with just a bit of discipline.