Never, i'm terrified i'll delete something that I shouldn't and corrupt the game! I only delete something if I realize it's not showing up or causing an issue and I know it should be fine to delete. I just keep a lid on how much I download because i'm at 10-15 minutes of loading time now and I think that's enough XD.

It's organized...to an extent. It could be better but it could be much worse.

Yes if you have any kind of cc that creates an NPC like a multi PT pack, a carnival ride or an animal and you pull it you have deleted a sim and corrupted your hoods. If you pull social mods you can create the Debug Super Hug. If you use mods that give sims a token they might also have instructions on removal.

Yeah I created the super duper hug bug awhile back...it's long gone now though.

Never, really. Sometimes I go to bodyshop and delete a couple of hairs or pieces of clothing because they did not look as nice in game as I thought or I got a retexture that I liked better, but I never go through all my downloads systematically.

Not unless you reinstalled, it's there just not showing. Maxis code, can't kill it with fire.

I did It was a long time ago. Plus that was before the Ultimate Collection which is what I use now anyway.