https://de.wikibooks.org/wiki/Datensicherung/_Langzeitarchivierung#Haltbarkeit_von_Daten_auf_externer_Festplatte_erh.C3.B6hen
HDDs altern, wenn nicht genutzt...
The recommended storage period:•1 year under controlled conditions of 34°C 90%RH or less• 90 days in uncontrolled storage conditions
The maximum recommended storage period for the drive in a non-operational environment is 90 days. Drives should bestored in the original unopened Seagate shipping packaging whenever possible. Once the drive is removed from theSeagate original packaging the recommended maximum period between drive operation cycles is 30 days. During anystorage period the drive non-operational temperature, humidity, wet bulb, atmospheric conditions, shock, vibration,magnetic and electrical field specifications should be followed
https://www.seagate.com/www-content/product-content/hdd-fam/kinetic-hdd/_shared/docs/kinetic-product-manual.pdf
Maximum storage period within shipping package is one year
https://documents.westerndigital.com/content/dam/doc-library/en_us/assets/public/western-digital/product/hgst/megascale-4000-series/product-manual-megascale-dc-4000-b.pdf
Das schreiben die Hersteller nicht umsonst, mit der Lagerdauer steigt immer auch die Ausfallrate und AFAIK nach nem Jahr ohne Betrieb noch einmal extrem!