In a discussion on FB about writing techniques, I brought up research.
I often leave holes in my manuscript with notes to do more research about this or that.
One day I abandoned my family, got into my car and drove down to Williamsburg, VA and spent the weekend there taking pictures and doing research. Yes, I found the answer to one of my editor's burning questions and to my relief was able to state it in one paragraph, not a whole chapter.
I took a day trip in December to Washington Crossing, PA to watch the reenactment of the crossing and take photographs for my biography of George Washington. In 10 degree weather. Taking photographs with insulated thin leather gloves. (They turned out great)
I actually took THREE trips to Washington, DC to wander the Air and Space Museum so that I could explain flight so that everyone (including me) could understand the physics behind it.
I got a lot of praise from readers and reviewers for that one point (plus a lot of awards for that book, so it was worth all the research.