What’s the most dramatic failure of a low‑quality component you’ve seen, and how did you diagnose the root cause, evaluate the impact, and prevent it from happening again? We are asking e14 in our Join, Share & Win Competition

I bought a set of jumper wires, but the insulation was so saturated with plasticizers that they melted through my storage container. I quickly took them to the municipal hazardous waste facility.

Snubber capacitors go off like grenades and leave a sticky mess everywhere. Realized if the snubber resistor failed, blame the cap. Change both with trusted vendor components and youre good to go. 

Just to clarify here, what you are saying is that the chemicals in the insulation layer plastic were so bad in quality that they leaked out of it and left the marks we see on the picture? 

yes that is exactly what happened.

For me it was the SG90 servo motor soldering coming off , I was making a dry waste and wet waste segregation system using servo and soil moist sensor, but the soldering kept coming off, I instead could not get a soldering iron because mine old one stoped working and getting a new servo was easy then getting a soldering iron but this kept happening again and again until we had bought almost 6-7 servo motors , this forced me to always keep a soldering iron with you , soldering irons are like white blood cells of your projects...

RF attenuators are not necessary a low-cost component, but I’ve found inexpensive attenuators have a number of issues to watch out for. Issue #1 is their power ratings. The maximum power rating covers the whole frequency spectrum of the measured signal. You may have a main frequency of interest (MFoI) that is under the max power rating, but other frequencies, including harmonics of the MFoI, can cause the max power to be exceeded. Issue #2 is inexpensive connectors cause poor repeatability in measurements. More issues to follow…

What issues have you found?

In the past I had load of failures when using cheap Arduino clones for no apparent reason. The worst case happened with a pack of four Arduino Micro clones: they all worked initially but within few days they started acting weird. Some were no longer recognized by my PC, others still worked but wouldn’t retain the program in their flash memory. I spent so much time and frustration just to realize that the problem was the Arduino, not my project.
The solution? Buy the genuine stuff (or at least high quality parts). I was in high school and back then time was cheap and I had no money, but I learnt from that experience. Nowadays my approach is to buy genuine or high quality components (or instruments), that will reliably do the task I have on hand and will hopefully last a long time. No more wasted time for dubious quality hardware!

Maybe it's not fair to say these are cheap components but power ratings for certain power resistors are misleading.  This wasn't for a design per say but I had to create a test load.  Unfortunately the specific details of this adventure are murky but to stay on the safe side I decided to use 4 resistors to make the test load.  If I am not mistaken the power rating of each resistor was 5W. Well once power was applied it didn't take a second before the air was filled with that old familiar smell.  It should be said that the resistors I used were bulky and substantial through hole parts, and although they had considerable size they were still suitable for board mount.  After this fiasco I wasn't going to fool around.  I bought some of those large corn-on-the-cob size ceramic core power resistors and I haven't looked back... they have been my go-to anytime I need a test load.

Scary.

Thanks robogary I was thinking of using a flyback transformer to create a high voltage so when it comes to the snubber I will follow your advice regarding trusted vendor components.