Why do I need more time and liquid than my risotto recipe calls for? Whenever I make a risotto, I always find that I need about 50% more liquid and 50% more cooking time than my recipe suggests. I recently made a Jamie Oliver risotto that called for 1 cup arborio, 2 cups chicken stock, and 20 minutes. I used more like 3 1/2 cups of stock and it took a good 30 minutes. My stock is heated in a separate sauce pan, and I add it a little at a time (although probably more than a ladle, maybe two?). I stir frequently but not constantly (probably once a minute). I consistently seem to have this issue regardless of the recipe source.

Am I do something wrong? Or is this a case of a recipe playing it on the safe side?
It doesn't sound like you're doing anything wrong. I've found risotto to be one of those recipes that can vary up to 50% (usually less) from what the author calls for and still turn out great. I've even used recipes that call for "2-4" cups of broth. You may be overcooking it though, the rice should be al dente. It's not uncommon for people to overcook this until you have a mushy risotto.