You’re right that there are extremely rare exceptions (though even official sources like Purdue OWL and Chicago manual of style disagree on the finer points), but I will keep telling everyone you never, ever use it for plurality. I would be much happier seeing people type “there should’ve been WotLKs for users to choose between” than “I had three burger’s” on the very rare chance I see the former. I hope you’ll join me!