One should always fold a talis as soon as possible when finishing to use it, as it is considered respectful for the talis to stay folded. Likewise, it is written in certain seforim that it is considered a sakana, dangerous, to leave a talis unfolded. On shabbos, one is not allowed to fold a talis, although the halacha tells us that if one is folding the talis in an irregular way and not in its proper folds, it is not considered mesaken keli, fixing the talis, and it is therefore permitted to fold it shelo keseder kepulo horishon, not in the order of its original folds. Nevertheless, there are some people who are makpid, particular, and they still will not fold a talis on shabbos, even in an irregular manner. Additionally, there is a particular inyan to fold the talis on motzei shabbos immediately, so as to right away start motzei shabbos with a mitzvah. Some suggest that this could even be a segula for sholom bayis, helping strengthen marital harmony.