David Allen: At any time you can decide to do something that takes more than two minutes–you’re just deciding that’s the work to do at that moment, vs. “processing” your inbox to zero. Could be lots of reasons that it’s the thing to do. Also, if you’re on a five-hour plane ride, you can spend as much time as you want on any of the items as you’re cleaning up your email, if you figure you’ll finish by the end of the trip anyway. No hard fast rules about any of that. The point is, if you want to see all your work, current, you can’t do that until your inbox is empty and all the work has been defined. And if you want that to happen asap, don’t spend longer than two minutes on any one item.