How long will unused hard drive last?

Our company wants to do some local (non-cloud) backup, I'm thinking the easiest is to get some high quality external hard drives, copy the data onto them, detach them, then store the drives in a climate-controlled environment. I'm imagining having two sets of drives that I alternate monthly backups.

How much "bit rot" will there be on drives that are sitting on a shelf, powered down? The lifespan of drives seems to always be given in terms of hours of actual use - and in this case that would be a very small number.

Solution 1:

Use tape for long-term archives and multiple public clouds (multiple tape-in-cloud still as no way anybody can store PBs of "ice cold" data on anything except tape). Hard disk isn't designed to store data for a long periods of time. 3-2-1 backup rule is in power either way.

https://www.starwindsoftware.com/blog/3-2-1-backup-strategy-why-your-data-always-survives