One of the problems is that the onset of tin whisker growth is stochastic. In other words, we can't predict when they will start growing, it's random. Which means they can start growing in a day, a week, a month or three years.

If I remember correctly, once they start growing the growth rate is reasonably constant and can reach many millimeters per year.

If that doesn't sound bad at all, keep in mind that fine pitch integrated circuit pads in modern electronics could be in the order of 0.2 mm apart. Which means a tin whisker that grows at a rate of 10 mm/year could bridge that gap in about one week.

I could be wrong on this, but it is my opinion we will eventually discover the RoHS initiative backfired and we generated more consumer waste than we every had before RoHS. I still have my 30+ year old HP-41C calculator (as well as a small collection of other HP calculators). They all work perfectly. They don't have lead-free solder. I doubt any RoHS era calculators will be able to survive that long and still work. In other words, we are likely filling our trash dumps at a faster rate than ever before due to RoHS.

RoHS: https://en.wikipedia.org/wiki/Restriction_of_Hazardous_Subst...

This has been an open problem in materials science for like 70+ years — https://scholar.google.com/scholar?hl=en&q=tin+whisker

There’s been plenty of work, but It’s a hard one to elucidate physical mechanisms for because they are super rare in terms of the number of potential initiation sites... You have to get lucky if you want to observe the material state before the whisker formed

It’s become more of a practical problem since the restrictions on leaded solders, since lead-free solder alloys seem more prone to whisker formation...

Yes. A startup where I worked built an internet appliance that had a socketed chip modem. One failed mysteriously, pulling it out and testing it, it worked, plugging it in, it failed. Looking closely at the area below the socket a tin whisker was pointed straight up from one of the socket pins. Almost impossible to see unless you looked at it at just the right angle.

Yes, I've seen RoHS-related whisker issues in production hardware, although not related specifically to lead-free solder. These whiskers [1] appeared on the body of a PCB-mounted TNC jack from Amphenol, a US-based vendor.

It's very upsetting to see this happen to your own hardware, just because some EU bureaucrats believe that long-lasting electronic products are a bad thing rather than a good thing. Fortunately, 6 years down the road, it appears to have been a one-time incident.

[1] https://imgur.com/kmb2mtZ