As stated, just leave it in tea and it lasts... forever. Well, with a little pick me up every once in a while. I've got a Jun scoby and a regul;ar scoby going quite well for a couple of years. Whenever I think of it, which is about every six months or so, I 'revitalize' them with some freshly brewed tea. I use a quart-size jar and leave it to be in a nice dark place, undisturbed.
Haven't had the need to drink the tea for a while as it's a powerful 'medicine' when needed but I keep it alive 'just in case'. It's awesome stuff in the right hands.