If you think of a new next action, the key is that you capture the next action somewhere so that you can get it off of your mind and not have to worry about forgetting it. As others have noted, if it is a two-minute next action and you are in the right context, you can go ahead and do it. Otherwise, you can add it immediately to your next action lists or put it on one of your inboxes for later processing. If you need time to think about what the next action is, then your next action is to evaluate a new next action for project x. You certainly can have more than one next action for any given project on your context lists as long as they are independent of one another. The downside of this approach is that your lists may get too unwieldy for a quick scan. For this reason, I try to limit multiple next actions to only a handful of projects.