How do you handle archiving old mails in your maildir?

#!/usr/bin/env zsh
where=(--where .)
zparseopts -K -E -D -A opts '-where:=where' -days:
if [[ -z ${opts[--days]} ]]; then
    opts[--days]=30
fi
opts['--days']=30
if [[ $# != 2 ]]; then
    cat <<EOUSAGE >&2
Usage: $0 [options] from to
Moves old emails

Options:
    --where PATH Path to move emails from; that is, move <from>/PATH/x/y/z to <to>/PATH/x/y/z
                 If omitted, assumes '.': every email inside <from> will be moved
EOUSAGE
    exit 1
fi

from=$1
to=$(realpath $2)

cd $from
echo find $from -type f -mtime "+${opts[--days]}" -print
find ${where[2]} -type f -mtime "+${opts[--days]}" -print |
while read f; do
    mkdir -p $(dirname $to/$f)
    mv $f $to/$f
done

And then I run archive_maildir.sh ~/Mail ~/Mail/Archive --where folder_I_want_to_archive --days 15

NOTE: my setup is ~/Mail is indexed by notmuch; ~/Mail/accountname for each account I have. Moving the mail to ~/Mail/Archive/ does not create any problem to notmuch.