After a few bad experiences with some durians vendors who will insist that the durians opened up are good enough to be eaten and you have to take them. Since then, I decided to learn to DIY (choosing my own durians and open them myself at home). Since it is DIY and I am no expert in choosing durians, I will have to buy more (around 8-10 depending on the size) and bargain for 2-3 more FOC durians to compensate for bad durians. I will always expect to throw a few bad or not-so-good durains and it is EXPECTED!
Similarly, for stock picking for my DIY Portfolio I will always EXPECT to throw a few bad counters. So far I was hit by two counters that went to ZERO and by now probably I may have learned enough to avoid picking that next ZERO counter.