Writing Endings in Trilogies

It strikes me that there is a world of difference between writing endings in a stand-alone novel and endings in trilogies. In the former, the story should reach a conclusion that, even though it may leave the door open for a return to this character or situation, nevertheless should leave the reader feeling that they have reached the end.

On the other hand, the endings in volumes one and two of a trilogy should also act as a springboard into the next volume.

Arcs versus endi...