GUI/CLI licenses are not required under the following situations:
Running the CLI version to back up personal files/documents on a home computer
Running the CLI version to restore, check, copy, or prune existing backups on any computer
Running the CLI version to back up any files on a computer where a GUI license is already installed
Running the web-based GUI (Duplicacy Web Edition) to restore, check, copy, or prune existing backups
The CLI version is free for personal use. In addition, if the operation is to restore or manage existing backups (such as check, copy, and prune), the CLI version can be run by anyone on any computer without a CLI license.