I was working on a file for a friend and when I was finished, the file size
was about 1k. When she did the process, it was over 35k and even had one
file over 128k. I was impressed by the size and I watched her do the
process from scrach, it was 35k again. We are working on only one sheet of
data to copy that is only about 1,800 lines and 46 columns. When I took her
big file that broke and did past onto a new sheet, it was large again so I
had to do past special values then format the columns like dates.

any clue why some Excel Files are large?