>you still need to change your velocity in the exact same amount on both ends of the trip You usually need to change your velocity more than that. Cycler orbi

>you still need to change your velocity in the exact same amount on both ends of the trip You usually need to change your velocity more than that. Cycler orbits are more constrained in their start/end dates, so there are fewer free parameters to "tune" for lower propellant consumption. Generally a cycler with a 4 month transit time will need slightly more delta-v vs. sending a ship on a regular old transfer orbit with an identical 4 month transit time. This is because when designing a cycler orbit it's usually necessary to shift a few days ahead/behind the optimum dates for a 4 month transfer, in order to efficiently "stitch together" with the previous/next orbit cycle.