How often should I feed sourdough starter stored in the fridge before baking?

The title gives the gist of my question. I've been following Ken Forkish's instructions in Flour Water Salt Yeast, but storing my starter in the fridge and feeding it once a week or so with 25g starter, 100g water, 25g WW flour, and 100g AP. However, when I take it out to bake with, I've been noticing that it takes a couple days of once a day feeding for my starter to start doubling in 12 hours. In the days prior to that, I'm getting like a 40-70% rise in 12 hours. If I feed my starter every 12 hours, can I shorten the time it takes for the starter to be ready to bake with out of the fridge? How do you recommend I feed my starter out of the fridge to revive it for baking?

 Thanks for your help, feels like I'm running up to a wall after baking loaf after failed loaf, so any advice is very appreciated!