batch: move files accessed for a long time

I like to move files accessed for a long time. For instance: if I do not access some file by 7 days, it move to old sub-folder.

file1.txt    1 days         <keep>
file2.txt    2 days         <keep>
file3.txt    4 days         <keep>
file4.txt    7 days         <move to old>
file5.txt    10 days        <move to old>