This can be achieved combining two preferences in System Sertings > Desktop & Dock, under the Windows section:
1. Turn on “Ask to keep changes when closing documents”. This way documents do not retain changes until you explicitly tell them to.
2. Turn on “Close windows when quitting an application” which prevents documents from reopening the next time you lunch the app, but most importantly, as per the previous preference, prompts you to save or discard your changes.
Bonus points:
If in System Settings > Keyboard > Keyboard Shortcuts > App Shorcuts > All Apps you assign Cmd + Shit + S to “Save As…”, the Duplicate command is replaced on all File menus with Save As… and only reappears when you press the Option key.