Brooches and rings. In UK in some families these will be passed down to couples marrying as a gesture of continuity. In Birmingham, we have a 'quarter' that has many small workshops that make and repair/alter jewellery. Some of the older companies have design patterns/dies going back to the Victorian era.

I agree with your basic point: we all buy so much that is basically landfill.

I think we can go a fair bit older than that.

The Imperial Regalia of Japan, if it still exists, is... really old. I can't find a date.

The anointing spoon of the British crown jewels dates from the 12th century, and is still used [2].

If we don't need something to be in continual use, then bronze age jewellery, or stone age flint knives.

[1] https://en.wikipedia.org/wiki/Imperial_Regalia_of_Japan

[2] https://www.royalcollection.org.uk/collection/31733/the-coro...

Ceramics and glassware can and do last generations. They're functional too but use is likely inverse proportional to longevity.

Leather goods last well, I have my father's belt but it's not in a state to pass down further.

Fountain pens. I have some fountain pens come down to me from my mother's student era.

Stone knives 3.3 million years:

http://archaeologynewsnetwork.blogspot.com/2015/04/worlds-ol...

Tutankhamun's metal ones from 3000 odd years ago look quite modern:

https://www.google.com/search?q=Tutankhamun+knife&num=20&tbm...

I'd say that knives can be either inheritable or usable, but not both. Like all tools they will be worn pretty quickly if used actively.

I'm pretty sure a TI calculator fits the bill for tech heirloom. It's very basic, just an Z80 cpu and a small LCD display. It's rugged and can last. Even with being outdated tech, they sell for as much as when they first came out and could definitely be "inheritable". And, because it doesn't aspire to be a general purpose computer, just do some fancy math, it's not going to be outdated (unless you count ubiquitous cell phones)

Pocket watches with a mechanical power source, if done properly last quite long.

Rifles are functional for a long time as well.

Knives.

Jewelry.

>> Somewhere on the continuum of abacus, slide rule. What's the computational era's equivalent? An HP-11, HP-12 series calculator?

I have my Dad's wooden abacus, which must be at least as old as I am (mid forties). It's obviously not Antiques Roadshow old, but as a child, I remember him using it for his bookkeeping instead of a calculator. He taught me how to use one, and as a kid, I got pretty quick at using it for simple arithmetic.

Of course, once tape calculators (and calculators in general) got cheaper, he stopped using it altogether. If I had kids, it's definitely something I would pass on.

The wedding band I wear was used by my grandfather (I wear it around my neck now, pain in the ass to remove it from my finger). I also have a 1961 mechanical watch that was a gift to my father from his brother-in-law, and now it's mine and it works perfectly good (mechanical watches, if serviced every 5 years or so, have an indefinite lifetime). Pocket knives also come to mind.

The novena is nearly unique with its FPGA, features for hardware hacking and expansions that let you use it like an oscilloscope or for software defined radio. It's supposed to be considered like a piece of bench equipment rather than a disposable main laptop, and it'll probably age similarly to bench equipment (i.e. much better than a basic laptop).

Stradivarius.