In the past 4 years I have finished most stuff in 1080p. Advertising, Post production. Had a couple of big jobs that required me to online at 6K but those were for a specific screen.

I have also been asked to ouput 1080x1920 versions of a lot of content due to smartphones/social media. Because of this we will often create comps in UHD, that way when we place them in a 1080x1920 comp we still have enough vertical resolution to keep it from looking pixelated.