My group only had one combat every other session or so in 3.X (but when there was a fight, it mattered!) and we plan to do the same with 4E. I don't think you really need to adjust anything. Combats are more fun with the Daily Powers in every fight; they whiff disappointingly often as it is. And if you have a plot/story that requires a time pressure on occasion just let the players know ahead of time that that is a possibility and they can decide whether or not to reserve their Daily Powers in a given fight.