IMPORTANT:
If, like me, you have several devices which could be "Send to Kindle" targets, it is very likely that one or the other of those devices will be your primary device at any given time. However, Logos only allows you to register a Kindle with your Logos account once, and never again. That's a problem if you want to send to a different device in the future.
However, there is a solution. You can change your @kindle.com email address. There is an Edit link next to your device's Email address on the Manage Your Content and Devices page. There you can change the email address of your device. You can use any string of letters or numbers, so long as it does not conflict with another devices address.
Register your custom @kindle.com address with Logos after you have changed it in your Amazon account. Then, if you switch devices, you will not lose the ability to send books to your new Kindle or kindle app from Logos. You can delete your old device from your Amazon account. After 24 hours, your custom @kindle.com address will become available again, and you can assign it to your new device, and regain the ability to send documents from Logos.
