I never installed Messenger mainly because I was satisfied with using Facebook app's messaging feature. When it was disabled in the app, I moved to using Facebook in the browser (uninstalled the app). They later removed messaging support in the browser as well so now I request "Desktop mode" when I want to read/write a message. What started as "I don't want to install another app I don't need" became "I will uninstall all apps by Facebook" and now I'm happy I never receive FB-related notifications, I only browse it when I feel like it :)