Movies I typically say 5 years, unless it's a classic like Citizen Kane. Outside from the classics, I feel like if people haven't seen a film in 5 years then they simply aren't interested enough to care.
Video games and books are a different matter though, I unfortunately know the FFVII spoiler and the Shadow of the Colossus spoiler, amongst others, but I go out of my way to avoid book spoilers.
I feel like, since there are so many books and video games, and, in my experience, aren't the regular topic of discussion among friends quite the same way that movies are, there is no statute of limitations on them. Everybody has different tastes, and people get around to books and games in their own time, so why ruin the fun