A general answer to this question is in order before explaining the specifics. Casinos rotate dealers for many reasons.
Dealer rotation helps keep dealers sharp and on their toes. It doesn’t want them committing mistakes when you’re betting huge sums of money at that table. Dealer errors, particularly habitual ones, can really cause a casino to lose money and so it is in their best interest to curtail these types of mistakes as much as possible, both through training and rotation.
An example of this type of error would be making payouts without first calling for a supervisor’s approval. In the event one slips by, the casino will suffer a significant monetary loss. Another example would be stacking chips in a manner that makes them easier to steal. Dealer rotation helps prevent these types of behaviors from infecting other dealers who work at the same table when they take over for their co-workers.
More often than not, dealer errors are caught by pit bosses or surveillance cameras. There are more of these than there are dealers so it’s not difficult to see how rotation helps here. The main thing pit bosses look for is whether or not the dealer rotates cleanly and follows directions once he or she is told that they will be taking over someone else’s table. This ensures that orders come through clearly and that dealers are not making mistakes related to the particular way they have to move about the table.
Casinos also rotate dealers in order to keep players more engaged. This is often done during slow periods when casino traffic is low and/or when there are fewer tables open. Even if a dealer makes no mistakes at all, he or she may be rotated based on this factor if it becomes apparent that the dealer is not keeping players at the table. This is done by making an announcement to all casino patrons and by having security personnel circulate about, reminding people that there’s a new table open with a fresh set of dealers.
Preventing boredom and exhaustion
Casino rotation also helps to prevent dealer burnout and exhaustion. Dealers work hard, sometimes for days on end without rest. This makes them more prone to making mistakes due to fatigue and so dealers are rotated every so often in order to keep them fresh-faced and sharp.
Another related reason is to prevent players from becoming too comfortable with the dealer at their table. It’s much harder to win money if you’re playing with someone who knows your betting patterns and habits. Rotating dealers every few hours helps to mitigate this problem since the dealer won’t have enough time to familiarize him- or herself with each player’s specific tastes in terms of how they play, when they play, where on the table they like to sit, etc.
Some casinos rotate dealers more often than others. In general, high stakes casinos that host a lot of A-list players rotate at least every two hours while low stakes joints may only break up the monotony by changing dealers once a day or even less frequently.
Dealer rotation is an ongoing process. Casino dealers are constantly being rotated around to tables based on these various considerations. This means that players at the blackjack table will have different dealers every so often, but it does not mean that they will never see the same dealer twice during the same gaming session.
It is therefore important for casinos to rotate properly, both to ensure that player knowledge of dealers does not become an undue advantage and to prevent dealer burnout.
Casinos that do not take these factors into account by rotating their dealers properly will suffer financial losses over time which will eventually lead them to go out of business.