I usually like to pre-weave one complete cross, but I'll start the string on the next cross after that by only weaving it through maybe three or four mains. When I leave the end of the string there in the string bed, I can quickly grab it and finish that cross instead of taking those couple of seconds on every cross to "find" the end and thread it. I guess I'll call that my "holding weave".
I usually stop doing this as I get down near the last crosses, since there's less room in the string bed. It leaves a second loop out the other side of the frame as the crosses are running in, but it's certainly manageable for me. It's just less tedious when the end is right there ready to grab 'n go. Compared to a complete pre-woven cross, this little holding weave runs much more diagonally toward the throat so that it's not in the way of the full pre-weave before it.