When I created the entry for Four-Card Suits, q.v., I faced the hypothethical question, Why not five-card suits? And the answer, as you might have guessed, is that instances where five-card suits are in opposition (in a meaningful way) are far, far rarer than two four-card suits (one of which might be longer than four cards, but the fourth card of which needs to be preserved). Still, it does happen, and the principles of saving are substantially the same, and the first of those principles is, Get Rid of Useless Cards First!
On the above hand, N-S reached 5 clubs, unwisely doubled, after East had done some spirited bidding in hearts, bringing the king of hearts opening lead, ruffed, of course. Declarer now took two rounds of trump, West sluffing the 3 of diamonds on the second trick. She sluffed the 3 of diamonds at the very first opportunity to sluff anything! Why, why, why?
I can't tell you how common it is, not that defenders throw the wrong card, exactly, but that they do it at their first opportunity. I'm not kidding. West, no novice, but one who indeed fancied herself something beyond expert, had two useless cards and chose to discard a useful one. Should she have known the 5th diamond would be useful? Oh, not at all. I don't for a minute say that that is obvious, but that the total uselessness of the other cards is.
The 5th spade can't possibly be useful on this hand. You're looking at 9 spades, so no one else could possibly hold a 5-card spade suit. And the 8 of hearts? Oh, in a stretch, you might argue that it will be a useful exit card, but even that seems a little far-fetched. To need an exit card, you're going to need to get the lead, and even that seems unlikely until late in the hand on the second round of spades.
Actually, the discard of the 8 of hearts would have been academic here, for declarer now led a diamond to the king and East's ace, and East now made a safe exit with a second heart lead. So if the eight of hearts had been jettisoned, now would be the time to throw that 5th spade.
One of the reasons for throwing useless cards first, aside from the obvious that as long as you're throwing useless cards, you're not throwing useful cards, is that by the time you have to make a crucial decision, the hand might be clarified -- as it would have been here. A third round of trump might seem to give West a problem about whether to discard a diamond or spade, but declarer cannot lead that third round to his advantage because he needs dummy's trump for ruffing two low diamonds. So after re-capturing the lead at trick five, declarer now leads the top two diamonds, sluffing hearts, and ruffs the fourth round. He now cashes the ace of spades and gives up a spade. On regaining the lead, he ruffed his fifth diamond, though on West's sluff that was a good card, the last diamond remaining.
So what's the loss with the diamond discard? Declarer could and did ruff out his low diamonds and make his contract. That much is true. The contract was cold from the beginning, and doubled, might not gain much on the overtick. Nevertheless, on the Q J of diamonds, if declarer sluffs spades, ruffs a diamond, gets back with a heart, he now can sluff a third spade on the fifth diamond, for an overtrick by way of ruffing the closed hand's last spade in dummy.
The sluff of the diamond wasn't to have any effect on this hand because declarer didn't notice! Further, being doubled, it probably wouldn't have mattered a whole lot if declarer had noticed. Still, I think it worthy of note because on another hand, or on different bidding, that sluff of the fifth diamond could have had tremendous importance. East might have bid five hearts as a worthy sac. East indeed can make five hearts on anything but a diamond lead. Cash out a "safe" club, mister, and East can now sluff a diamond on spades, even on a quick shift to diamonds.
I also think it important to note that one can sluff enough spot cards from the long spades in order to ruff the last spot card from the short hand, which two presumably experienced players didn't notice. With declarer sluffing hearts on the Q and J of diamonds, he not only isn't sluffing spades he could to advantage, but he has no quick re-entry to his hand and so cannot use the 5th diamond for anything..
And if East can make five hearts except on best defense and might have bid 5 as a sac, South certainly might have bid 6 clubs as a sac, and then that fifth diamond is worth its weight in gold. On such circumstances are wild swings from plus 10 IMP's to minus 10 based.
A 10 9 8
10 7 3 2 
K 
9 5 4 2