How do I delete my Snapchat account for good, and is there a waiting period before it's gone?

You can't delete it inside the app, which is why it's hard to find. Go to accounts.snapchat.com in a browser, log in, and choose 'Delete My Account'. The important part: Snapchat first DEACTIVATES the account for 30 days, during which it's hidden from friends and you can reactivate just by logging back in. Only after 30 days of no login is it permanently deleted, wiping your snaps, Memories, friends and Chat history for good. So to truly delete it, submit the request and then don't log in for a month. Download your Memories and data first from the same accounts.snapchat.com page if you want to keep anything.

The 30-day deactivation trips people up. Logging in even once during that month cancels the deletion and brings everything back. To actually delete, submit it and stay logged out for the full 30 days.