Living off the land
That is a learned skill. Better to learn it closer to home than on Mars. Inevitably there will be things that weren't thought of, weren't accounted for. The moon is an ideal testing ground for much longer and more dangerous Mars and asteroid missions.
I have to say I'm skeptical about another space station project. ISS has for decades sucked up the massive budget that could have gone to human deep space exploration. An L1 space station could very easily end up doing the same thing. Eventually an L1 station is a must but why postpone all moon and Mars missions in the near term? We don't need every step to be a baby step.