In a suit contract the problem most declarers face is the timing of the trump extraction. For when the dummy comes down the declarer's primary task is the count of his winners, and losers in order to strike the perfect balance, which can yield him the required tricks for making his bid contract. Of course in such a context, the bidding of the opponents, if any, and the nature of the opening lead are very essential considerations in determining the timing of the trump plays.
For it is entirely based on the immediate need to develop winning tricks, if short. For in many instances while it is wise to extract trumps when an enemy ruff stares at you, at times the declarer will have other options to consider before he can draw trumps. For there is after all a race going on between him and the opponents and it is not expected that in such a duel, opposition would be friendly enough to help the declarer in the making of his contract. On the contrary, a tough opposition can pose awkward choices for the declarer depending on their defence strategy, which can range from an active defence to a passive one, from a straight forward defence to a deceptive one. At all cost, the declarer has to be on his toes all the time for one slip by him can cost him his contract. Let us take our first example in this context and see what's to be done. The contract is 4H by south as per the following bidding on this deal taken from a European Championship between two good teams:
The bidding: South 1H, N2C, 2H, N4H. The opening lead is the diamond king. Place yourself in the south seat and look for a way to make your contract of 4H. As usual, you count your possible losers first. You have 2 in diamonds none in clubs, 1 in spade provided you can manage to get rid of your two spade losers, either by ruffing in dummy or by the establishment of the club suit for possible discard.
At the outset, the thing to be noted is what if the opening lead had been a trump? A spade would induce another trump lead giving you just one possible spade ruff leaving you with 2 diamond losers, the ace of spades and a spade loser for down one.
Therefore, you should consider the opening lead of a diamond as a lucky break for you for now you have the initiative of being able to ruff both your small spade losers after immediately playing a spade to the king in dummy. But even here there is a little matter that needs to be thought of the back entries in your hand to extract trumps after ruffing the first spade on the opposition's trump attack, returning via king of clubs you ruff the last spade with your last trump in dummy.
Now you need to get back in hand to draw trumps. And the only way is via a club ruff for which the ace of club needs to be played. The danger that can come is if one of the opponents holds a singleton club. For then the ace of clubs well be prematurely ruffed before you can extract the trumps for which you so desperately need to come back to hand.
The moral of the story that needs to be learnt it that even when you hold such a massive trump holding, it plays to be diligently patient and take precautionary measures to time your trumps well. For even one round of trumps here would mean certain death while postponing it risked a club ruff of opponents. But then a little risk is always better than certain death!

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North       South
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    K         987
  765      AKQJ10
A1053         642
A9654          K8
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