my cousin's grandfather is 101 and lives in the house he lived his childhood in; i think he was born there. he and his parents have expanded the house significantly since then, as well as, of course, repairing and maintaining it. it's very comfortable now. a society that builds durable housing stock is saving up the goods and services that went into its construction
one of the things in the house is a nearly complete collection of national geographic magazines, going back before he was born; a treasury of knowledge about how people lived all over the world during that century-plus, as well as how they were seen from the point of view of the usa, ready to be perused and enjoyed at any moment without tracking cookies, broken links, images scanned at the wrong settings, or javascript incompatibilities. the images are mostly "retina display" resolution and famous for their beauty. preserving them for this century-plus has consumed very little resources
right now i'm listening to a song by rush recorded 40 years ago; every year there is a wider variety of recorded music available for me to listen to and compositions for me to sing, as long as we don't start losing it faster than it is recorded
last night i washed a shirt i got as a gift 17 years ago; if i can keep it from getting eaten by moths or sour sweat, it will surely last another 13 years
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but these are mostly consumer goods, not capital goods like lathes and motorcycles; having more shirts, national geographics, or rush songs won't increase my economic productivity, which is what is needed for such savings to grow rather than shrink more slowly (though plausibly you can be more economically productive if you have a house big enough to set aside a space for sewing or grinding telescope mirrors or enlarging negatives). and for that it isn't necessary for the actual material good itself to survive for decades; it is only necessary for it to augment economic production by more than its own value during its lifetime, however short that lifetime may be
a car may have a lifetime of 10 years and, by enabling an uber driver to provide higher-value services than they otherwise could have, produce twice as much value as its inflation-adjusted cost of manufacture over that lifetime, 20% of the cost of manufacturing it every year. multiply that by the number of uber drivers in a society, and you have savings growing, in real terms, on a societal scale. and there are a thousand kinds of capital goods like this which continue to produce real value over a period of time once savings have been invested in them: house insulation, refrigerators, washing machines, olive trees, engine lathes, kitchen knives, electric drills, laptops, and so on. even factors of production that are consumed within a few months or a year can qualify, like knitting yarn
(however, a drill you buy, use once, and then leave in the garage and never use again does not; it may not be decaying very fast but it's not growing)
this is how a society can grow its savings in real terms on a societal scale, through accumulating capital goods and knowledge so that its productivity can increase over time