I did the same for the first movie, but with the next two I've been at BotCon so it's pretty hard to avoid such things.
I've seen TV ads plus more footage and it is enough that I have a fairly clear expectation of how the movie will go. That is disappointing but couldn't be helped.
I haven't spoilt myself more though by reading the comics/novel, any of the behind the scenes news that's leaked out over the last year and a bit etc.
Typically if I know there's a movie I want to see, I don't watch any trailers. I only watch trailers for films I'm unsure of, and once I've seen enough to know if I want to see it I stop watching. If I don't want to see it I keep watching. I very often stand up and leave the cinema rather than sit through a trailer.![]()