With a new Wolverine movie, Logan, on the way, someone asked if they were a continuous story to catch up on:
They’re really not. 1 and 2 mostly are. 3 (The Last Stand) was but was then retconned to mostly not happen (along with the end of 2). Origins: Wolverine was a highly involved origin story involving at least three characters since retconned. First Class was an origin for the team set
in the 60s. The Wolverine was a modern story for him after 3. Days Of Future Past was a sequel to First Class set in the 70s and a sequel to the others due to time travel and results in the retconning of 2 and 3. Apocalypse was a sequel to that set in the 80s (which also retcons some more of 2). Deadpool pretended that his appearance in Origins: Wolverine didn’t happen even though he’s played by the same actor.
I think that’s everything...