Reset showthread.php?t=X & forumdisplay.php?f=X
 

Is it possible to delete all forums/threads/posts and somehow reset the numbering of those options? This would be on a bored never open to the public.

I am a bit OCD when it comes to numbering and I don't know what my final category/forums are going to be, and when I get the final down, I'd like to delete all of my current ones and have them start at 1 again.

How hard is this, and how would someone go about doing it?

Just truncate the forum/thread/post database tables
I wouldn't recommend this though so do it at ur own risk

Why not just reinstall the site and then you won't have any posts/threads/forums/users.

It would delete all of the modifcations/template changes/ and anything else set up.

Well then, go to the Forum Manager page and delete the forums. I think it will delete the threads in the forums too. Your server may not like this if you have a large amount of posts in the forums, so you may need to delete all the threads via Threads > Prune first. After that is all done, you could edit the tables (forum, thread, post) via phpMyAdmin to set the auto_increment back to 1. I would definitely do this on a test database first!!!! And make sure you have a backup database before you try anything.