In Cardcassonne, players place their cards in different rows to increase the scoring for that row. Whether in the field, the city, the road or at the abbey, you must ensure that cards placed will earn you more points than your opponents.
However, sooner or later, every player has to claim one of these series of cards to get points. If you wait one more turn, there will probably be a greater number of cards in the row. By cons, it is possible that another player take the opportunity!