Blackjack, like most table games, has an extremely high Return-to-Player (RTP) percentage. In the case of blackjack, this is over 99%, meaning that over 99¢ of every euro is paid back to the player in winnings.
That is the theoretical RTP. In reality, human beings often make poor decisions that lower the effective RTP.
When to Hit
Presuming everyone is familiar with the basic rules of blackjack, we'll take a look at the conditions in which a player may want to take another card.
The first consideration is the player's cards. If they have drawn an 11 or lower on their first two cards, the decision to take a card is academic: do it and get closer to 21.
Once the player's hand is valued at 12 or greater, the dealer's showing card needs to be considered. If the dealer is showing an 8, 9, 10, face card, or an Ace, it's not a bad idea to take a card if you have a 16 or less. The chances of the dealer beating your 16 or less are pretty high, so taking a card, even though there is a decent chance the player will bust, is generally the smarter play.
If both the player and dealer have bad hands, say the dealer has a 3 showing and the player a 12, hitting is the better play. The chances of the dealer landing two face cards are less than the player busting on that 12.
If the dealer is showing a potential bust hand with a 5, 6, or 7 revealed, the player may want to consider doubling their 8, 9, 10, or 11 hands. The disadvantage with doubling is that the player is restricted to one drawcard. Say, for example, the dealer is showing an 8 and the player a 9. In this case, doubling is a risky proposition. Anything under 10 or a face card is going to put the player at a disadvantage. If, for example, the player draws a 2 in this position, they are likely dead in the water absent an unlucky draw for the dealer.
On the other hand, if the dealer is showing a 6, then doubling that 9 is a good bet. Even if the player draws that same 2 again and finishes their hand at 11, the chances of the dealer busting with that 6 are high.
When to Stand
The dealer holding a bust card is the primary indicator on whether or not a player should stand on a hand in blackjack. The 5, 6, and 7 cards are the most likely to produce a bust for the dealer.
Another instance where a stand is the smart move would be when the dealer is holding a 7 or higher and the player has a pair of face cards. Some players are tempted to split too often. In a case like this, take the 20 and the almost guaranteed tie or win. Now, if the dealer is showing a 4, 5, or 6, then splitting those face cards is a good move. Chances are extremely high that at least one of those split hands is going to be a winner.
There are no Lucky Hands
There are good hands and bad hands, period. One thing that gets players in trouble is that some have a particular affinity for a set of cards. While this is more evident in games like Hold 'Em, blackjack players are not immune to these tendencies.
Just because a player wins big one evening with a particular set of cards or even several times with this so-called "lucky hand", it doesn't change the percentages. Over time, the math will win. The best blackjack players are those who remain disciplined about following the percentages. Check out this handy cheat sheet that tells you how to play by the percentages.