How long will It take for the red boxes under Marvel Now comics and The New 52 symbol to disappear?
I can't speak for OP, but The New 52 isn't so much about being obnoxious as being unnecessary...like, how long will they make a deal about it being "new?" We're already into the 17th issue of many of these books.
The Marvel one, though, that's flat-out hideous, and covers an inexcusably large portion of every book (not unlike the banner ads DC has also taken to including, such as for Arrow).
I may be mistaken, haven't got many left in my set, but pretty sure the Marvel NEXT! tagline in the early 2000s was only on for the initial arcs...sometimes just the initial issues. So I reckon it'll disappear soon.
New 52, however, may be treated like Elseworlds or Ultimates, and remain indefinitely to indicate what universe titles take place in.
I really wish they would strip off the ''Arrow'' tv show advertisement too, its annoys the crap out of me, But I think DC will remain ''The New 52'' for archive sake and will remain so until the next reboot, and I can't comment on the new Marvel launch yet because it's been awhile since I've been to the comic shop