sourdough starter revival

I agree with Carol - go by the look, feel, and smell of your starter before following any hard and fast rules. You'll eventually need to split your starter - sure you might not need to the first or maybe even second feeding, but as Carol mentioned you'll eventually have too much. But there are some great recipes for "discard" starter on King Arthur Flour's website including pizza dough, waffles, and pretzles if you, like me, felt it was just really wasteful to toss all that starter (their sourdough waffle recipe is my favorite!). As for the two a day feeding that's where I'd say go by how your starter seems - when I first started my starter, two a day feedings were preventing it from really growing. Even in warm weather, I got no bubbles or sourdough smell after a week of 2 a day feedings. I ended up doing once a day feedings and my starter took off, but other people swore by 2 a day because it worked for them. You'll know it's active again when it has lots of bubbles, and smells like your starter when it was active. In my starter's case it smells a little sour, in a clean, fruity way, not a bad way. Sometimes I think the fruity smell gives way to an alcohol smell and then I know I should have fed it a little sooner! But so far that hasn't killed my starter and it bounces back fast.

You definitely don't need to maintain your starter in such a large volume - what is important is the ratio of starter to fresh flour paste. When I've had a culture going, I kept it in much smaller volumes, more like a few tablespoons. I followed the Tartine instructions, which were to dilute it back to 20% once a day (discarding the undiluted 80%). After a little practice I eyeballed the amounts. With that method, only a tablespoon of starter is required to inoculate the overnight leaven, so these volumes were plenty and minimized waste. Even if you follow a recipe that uses more of the straight starter, just calculate back from when you're going to bake bread and scale up then.
I've also kept starter in the fridge for many months and revived it. It was a little weird at first but recovered within a few days.

Hi Rachel. I got to go to a wild yeast class at Slow Food Nation and learned a LOT about starters. Yes, you need to discard a portion of the old each time you feed to re-activate the starter. Ratio should be ~30% starter to 100% water and 100% flour. Seems counterintuitive but it works. I know because I had starter bursting out all over my kitchen -- even into the crevices of my Dualit toaster -- due to my resistance about dividing and tossing at feeding time! You'll know when it's active again. Best to go by look and smell rather than schedule. Also, there's a good tip on Food52 about drying your starter, which is what I did for safekeeping after cleaning up my voluminous mess!