If your hand isn't strong enough or you haven't formed enough melds, declaring too soon could leave you exposed. On the other hand, if you waitsatta up satta king too long, your opponents might finish their hands before you can leave. Declaring when you have two or three strong melds & little deadwood—cards that don't contribute to any melds—is a good general rule. It's also crucial to time your declaration according to how the game is going.