Declaring when you have finished a sizable number of melds & are certain that doing so will result in a higher score than waiting for more cards is a good general rule. Making this decision can be aided by fast download apkevaluating the current state of play, including the number of cards in the draw pile and the cards that opponents are holding. However, there are situations in which delaying declarations is beneficial. If you have multiple possible melds that could be completed with just one or two more cards, or if you see that other players are almost finished with their hands, it might be prudent to hold off on declaring.