A common theme I'll see in mentions of planned missions to Mars is that it would last about 2 years due to how the orbits of Mars and Earth align, this often coincides with the idea of a Mars Cycler: https://en.wikipedia.org/wiki/...
The cycler just seems to make lots of sense. I'm surprised it hasn't been attempted as a method to move probes and other unmanned craft to Mars and back. Or on a smaller scale, a lunar cycler. The propulsion needs for interplanetary travel are different than the needs for takeoff and landing. Separating them into two different craft just seems like a good idea to try.
grep me no patterns and I'll tell you no lines.