While some fans were upset that Avengers: Endgame had no post-credit sequence, which they are known for, it seemed fitting. The post-credit sequences were always a benchmark of what is to come. Endgame was the climatic conclusion of the whole Thanos storyline. Yet, now that the cat is out of the bag, Spider-Man: Far From Home will tease the upcoming aftermath of the events in Endgame.
If you have been avoiding the new Spider-Man: Far From Home trailer until after you have seen Avengers: Endgame, you may be in luck. However, you may want to arrive late to the theater. Online reports indicate that Marvel is adding the trailer for the upcoming Spider-Man movie as a post-credit sequence to the massive Marvel movie.
Given that Endgame doesn’t actually spell the end of Phase 3, Far From Home deals with the aftermath of the post-snap world, but will lay out the bigger vision for Marvel in Phase 4. Given that Disney has laid out some eight films for Phase 4, Marvel could be working on a smaller completion schedule, but no ten year plan like before. I have no evidence to support that theory, but that is a general feeling.
Reports indicate that the trailer that will occupy the post-credit scene will be the same trailer that was released online. Some reports indicate that the same trailer will/could appear before the film (with the Tom Holland) warning and then after. Unless you want to see the trailer twice on the big screen, you can bail after the main credits.
Just a tidbit of Hollywood history, trailers used to appear after the movie was completed. If you ever wondered why the complete credits appears at the beginning of the movie, that is why. Hence, that is why they were called trailers. So, some can say that Marvel is tipping the hat to old Hollywood. But, that would be a bit of a stretch.