There is one trap when starting a culture: baking bread too early. The levain will start to rise madly after 2-5 days, but this does not mean it's ready! It needs much more time (two weeks?) to become more acidic and develop a good balance of yeast and bacteria.
Once you get a good one, maintaining it is rather easy, though. Feed it every day, and if you forget for a day or two, it doesn't matter that much. It's fairly abuse-proof: for years I even left a portion of dough as the levain for the next bread, which you should not do, because it contains salt (which slows the development of either yeast or bacteria, don't remember now). Everything was fine.
It's all pretty magical: the levain doesn't spoil, because of the low pH. The bread also keeps for a long time (a week, easily).
Once you get a good one, maintaining it is rather easy, though. Feed it every day, and if you forget for a day or two, it doesn't matter that much. It's fairly abuse-proof: for years I even left a portion of dough as the levain for the next bread, which you should not do, because it contains salt (which slows the development of either yeast or bacteria, don't remember now). Everything was fine.
It's all pretty magical: the levain doesn't spoil, because of the low pH. The bread also keeps for a long time (a week, easily).