I've been using single-stage missiles exclusively to strike enemy ships that are within the fire control range of the ship that fired them.
I imagine multi-stage missiles must have some purpose, but I haven't yet figured out when I might want to use them.
I've also gotten the idea that you can create 'buoys' which are missiles that carry a payload of a sensor, rather than a warhead, and they last a long time? Or something?
I have this dim memory of long-ago creating missiles that could track targets under their own power, and therefore operate far outside the targeting range of the ships that fired them. (I may be remembering a different game altogether.)
This is all stuff I'd love to look up on the wiki.