I have a pile. I create kits and get the base done, and then put everything for that LO in a folder so that I can grab the tote and take it with me if I am going to a crop or traveling or just want to work on something I can get done faster because I already started it.
It depends. I usually have extra photos printed ahead to fill a page. So, sometimes I start with the photo, find a sketch extra. Other times I make up a few layouts using sketches and have them ready.