Is it a good policy to delete our question, when we found our question is duplicate of another question? or another policy which you suggest ?
I have found useful additional information in duplicate questions. Things such as flags set or solutions tried that affect my approach. If those questions are deleted, then that useful information disappears.
Is it possible to have a "Related" categorisation that might be reviewed as the information becomes too old to be useful? For example, when a suggested solution uses a deprecated function, or applies to an old kernel.