Dealer peek vs no-peek
Understand why dealer blackjack procedure matters.
Surrender allows a player to forfeit a hand before playing it out and recover part of the original wager. It sounds defensive, but in a small number of very poor situations surrender can have a better expected value than hitting, standing, or splitting.
Late surrender is the common modern form. The player may surrender only after the dealer has checked for blackjack, or under a rule structure that otherwise protects the dealer's blackjack priority. If the dealer already has blackjack, surrender is normally unavailable and the original wager loses according to the table rules.
Early surrender occurs before the dealer checks for blackjack. Because it can allow a player to escape some very expensive dealer Ace or 10 situations, it is much more favorable to the player and is comparatively rare.
The correct surrender decisions can change with deck count, S17 versus H17, and the dealer's blackjack procedure. In European no-hole-card games, the treatment of doubles and splits when the dealer later reveals blackjack can be especially important.
A surrender decision is mathematical, not emotional. You are comparing losing half a bet immediately with the expected loss from continuing the hand. When surrender is correct, continuing simply because you dislike conceding the hand costs value over time.
Many blackjack games do not offer surrender at all, and some interfaces hide the option until a qualifying situation occurs. Your strategy profile should match the actual availability and type of surrender.
Understand why dealer blackjack procedure matters.
Learn the no-hole-card implications.
Use the correct surrender assumptions.