Starter Refreshment Discovery
Over the years I have been feeding my starters using the "doubling at least" method to insure that the organisms got plenty to eat. That meant I would save say 100 grams of starter to which I would add equal parts by weight of water and flour ending with 300 grams of refreshed starter. I would take from that starter for baking and dump all but 100 g when it was feeding time. I never let the base mother starter get lower than 50 grams out of fear of loosing it.
What I have recently discovered is that I get a much stronger level of activity if I dump almost all of my 100% hydration starter out and start with basically an empty glass save the remaining amount after emptying the glass. I then add a few tablespoons of tepid water and enough flour to make a batter and mix it up. You only need enough old starter to make a milky mix when you add the water. I have even taken it a step further and added a little water to the empty starter glass, stirred it around a bit to make it milky and then poured the water into a clean glass and added flour to make a batter. 12 hours later it's all happy and trying to grow out of the glass. I suspect I am multiplying the volume by at least 100 times or more. The beasties seem to love it.
So, for those of you who are worried that you need to maintain a certain amount of starter as a base lest you don't have enough to inoculate the next batch. Worry not. You just have to experiment one time to learn how virulent these organisms are.