If those are your needs, you order all the parts you need over your product’s lifetime up-front or get (= pay for) a contract with the manufacturer that makes t

If those are your needs, you order all the parts you need over your product’s lifetime up-front or get (= pay for) a contract with the manufacturer that makes them promise to sell you the parts for X years (they probably wouldn’t keep producing old parts, but would stockpile enough of them to be able to deliver working ones years later) (Or you prepare for having to go to eBay for working parts. https://www.nytimes.com/2002/05/12/us/for-parts-nasa-boldly-goes-on-ebay.html https://www.nytimes.com/2002/05/12/us/for-parts-nasa-boldly-...)