Routine flights
I'm afraid science fiction writers made us believe spaceflight would go the way of the airflight.....
But it is so much more difficult that even a single stage to orbit manned space plane seems unrealistic and instead, the answer would be to build a small capsule (with a large crew), boosted by a 2 stage rocket, as simple as possible.
Instead of going back and forth frequently, stay as long as possible in space. Instead of using frequently with long repairs, use once and don't repair , but use it for a long time.