I'm writing a series and the individual books are being published three to four months apart. I try to give just enough recap to ground the reader in the world again, then move forward. It's something I struggle with myself - finding the right balance between re-orienting someone who's reading the series as it's released, and not boring a reader who doesn't have that lag time between books.
However much exposition you decide on, make certain it occurs in a scene where something else is happening. I originally opened my third book with my MC standing in a field brooding over past events, but even 200 words of it was too much, and I hacked out that pity party. He's still standing in a field brooding when the story opens, but I segued almost immediately into the introduction of a new character, and used that as a way to drop in the necessary exposition (being careful to avoid the dreaded "as you know, Bob" conversation).
One of the most important things I've learned here at AW is to R.U.E. - Resist the Urge to Explain. Trust that your reader is going to get it, and keep moving forward. If it's confusing, a good beta will let you know (or your editor will hammer you on it later).