"I thought once you have the grains, you have them forever, they replicate and you just keep re-using them and giving away the extras. Am I right?"........Yes, they grow and grow. You end up not knowing what to do with them, lol!
"What about the kind that comes in a package and can only be used once, like Body Ecology, is that any good?"....I have read that it isn't as strong or as beneficial as real kefir, but still better than nothing.
I stay away from the inulin and FOS, I never really noticed a direct connection, but read enough to make me choose supplements without it.