Duration

Duration is a card type that was introduced in Seaside (and returned to in Adventures). Duration cards are Action cards which usually have an effect on the turn after they are played. A Duration is not discarded from play until the Cleanup phase of the last turn on which it does something - usually the turn after the turn on which it is played.

On the turn on which they are played, Duration cards typically have weak effects (relative to their cost), or even detrimental effects; their strength comes in part from the fact that their effects on the next turn do not consume an Action to play or a card slot in your hand. For example, Caravan, on the turn it is played, is a cantrip with no effect; on the next turn, however, it gives you a sixth card in your hand for free—thus playing a Caravan on one turn has the same effect as playing a Laboratory on the next turn.

Although Duration cards' next-turn effects are typically quite strong, they cost less than and are usually considered weaker than cards that have those same effects immediately—for instance, Caravan costs while Laboratory costs . This is in part because it's better to receive benefits earlier—playing a Caravan on the last turn of the game gives no benefit while Laboratory does—and in part because the fact that Durations stay in play for two turns is a disadvantage, since it means that they can actually be played less frequently. For instance, it's possible to draw an extra card every turn by having a single Laboratory and playing it every turn; in order to play a Caravan every turn, you have to have two copies of the card.

The durations are Haven, Lighthouse
Fishing Village
Caravan
Haunted Woods, Merchant Ship, Outpost, Tactician, Wharf

A Haven played with no card in hand to set aside or a Tactician played with no cards in hand to discard will be cleaned up (discarded from play) at the end of the turn when they are played; in all other cases, the duration will stay in play until the end of the turn after it was first played.

When you Throne Room or King's Court a Duration, the Throne Room / King's Court also stays in play until the Duration is cleaned up, to remind you that the Duration's next-turn effect needs to happen twice or thrice. When you Procession a Duration, the Duration gets trashed, but it still has its next-turn effects, and the Procession remains in play until the time at which the Duration ordinarily would have been cleaned up if it remained in play. None of this applies to Tactician; since its main effect can't really be "throned", the accompanying card is discarded at the end of the turn, though Tactician is not.

Although the Seaside rules do not mention this explicitly, a Duration card still in play when the game ends is returned to its owner's deck before scoring; this can matter for alt-VP cards such as Gardens.

There are a couple of cards from outside the Seaside expansion that have effects on subsequent turns: Possession and Prince. Despite their functional similarity, these are not Duration cards and the Duration rules do not apply to them: for example, unlike Outpost, Possession is discarded before the extra turn it creates; and Prince is set aside to perform its future-turn functions, rather than remaining in the play area as Duration cards do.

Official Rules

• Seaside introduces Duration cards. These cards are orange, and say "Duration" on the bottom line, i.e. "Action – Duration." A Duration card does something after your turn. Leave the card in front of you until the Clean-up Phase of the last turn in which it does something (discard it before drawing for the following turn). So if the card says "Now and on your next turn," discard it during the Clean-up phase of your next turn.
• If you play or modify a Duration card with another card, that other card also stays in your play area until it is no longer doing anything. For example if you play Throne Room on Merchant Ship, both cards stay in play until the Clean-up phase of your next turn. The Throne Room stays in play to remind you that you are getting the effect of Merchant Ship twice on that next turn.
• In order to keep track of which Duration cards are discarded during the current Clean-up phase and which Duration cards remain in play, place Duration cards in a separate row above the other Actions and Treasures played. When a Duration card has its last effect, move it to the row of cards that will be played and discarded during the current turn.