In ball games the vital factor that makes the difference between success and failure is a sense of timing. This is the secret behind the booming serve, the flashing drive through the coven, the long tee-shot down the middle, and the header that leaves the goalkeeper standing. A fine coordination of eye and muscle results in the striking of the ball at precisely the right moment for maximum effect. It is the same story in boxing, wrestling, fencing, athletics, or any sport you care to name –the time element is of prime importance. This is also the case in spheres quite unconnected with sport, such as business, politics, drama and stock market speculation. The concept of timing is universal and can be applied to every form of human activity.
Bridge is no exception. The force of the time factor in the play of the cards is seen most clearly in those no trump contracts that develop into a race between the declarer and the defenders to establish long suits. The play of such hands is normally a simple matter, but the loss of a tempo through attacking the wrong suit will usually prove fatal. At the other end of the scale are the difficult hands involving end-plays, coups and squeezes. In all such advanced plays success is dependent upon precise timing. Between the two extremes lie a multitude of ordinary hands which are neither easy nor difficult. These are the hands on which the declarer or the defender has a number of jobs to do. The order in which these jobs are tackled will very often decide the fate of the hand. It is in this intermediate range that most of the common errors in timing are made. Here is an example.
West led the 
2 to the 9 and A, and at the second trick South led the 
10 for a losing finesse. East reasoned that since the defence appeared to have no diamond trick they would need two spades and a club to defeat the contract.
Accordingly he returned a low spade and the 
9 forced out dummy’s queen. The declarer drew the outstanding trumps and then returned his attention to clubs, but it was too late. West took the ace of clubs and shot back the J to defeat the contract. South’s sense of timing was at fault here.
He should have realized that there was no need for haste in the trump suit. His first task should have been to establish the clubs for a spade discard in dummy, thus ensuring ten tricks even when the trump finesse was wrong. South was fortunate that West failed to find the initial spade lead that defeats the contract out of hand. When you receive the gift of a tempo from the opponents it is a pity to hand it straight back.