When you're done with your first batch of kombucha, you can reuse the SCOBY (or kombucha mother) to make a new batch. Simply peel off the darkest layer of the kombucha and discard it, and then place the remainder of the kombucha back into the fermentation jar or bowl with your reserved kombucha. You can use this part of the mother to make a new batch of kombucha immediately or within the next few days.
Be sure to keep the kombucha mother in kombucha when you're not actively fermenting a batch of kombucha (preferably only for a day or two).
As your mother grows over time, you can begin to split off pieces ("babies") to grow into new mothers. You can use these to ferment multiple batches of kombucha at once, or you can give them to other people so they can ferment their own kombucha.
Ready to make a new batch? Make sure your equipment is sanitized, then proceed to step three: brewing tea for kombucha.