As you can see, sometimes you might get lucky – the directory is there, and since most home directories usually have the same name as the username which owns them, you can deduct that the username of the user id 1006 was "mike". You can now recreate Mike's account and it will be immediately reflected for all the files owned by user id 1006

The above statement is "partly" true. I say "partly" because if you create a user and then delete the user without creating another user, and then re-add the user, the above statement holds true.

But if you create a user say "james", create a user "john", delete user "james" and then re-add "james", the files/directories in "/home/james" will not reflect the new user "james". This is because the OS increments the id for each user added (except if the OS sees that the user being added was the last user added). Therefore if the original "james" had an id of 500, john would get "501″. And then the new "james" would get "502″. If you think that the new user "james" is the same as the old user "james" then you could change ownership of all files/directories under /home/james to the new user "james".