My travel became significantly less stressful when I sat down to make a list of the things that are TRULY irreplaceable on a trip. For normal business travel, there are two items on the list: my laptop and my contact lenses. Those two things would be a real pain to replace; anything else left behind can be solved by a quick trip to a store. I still try not to forget clothes, or nail clippers, but when I'm about to close the door to the house, I only obsess about the two things that really matter.