For example, tefillin may not be… … hung on a hook (i.e. from their straps; however, if they are in their bag, the bag may be hung. Likewise, they may be placed on a shelf or cabinet that juts out of a wall, i.e. not resting on the ground – unlike a ‘sefer Torah’, for which these may not be done either.) … left in a room in which a husband and wife sleep together, unless they are placed inside of another bag or covering, in addition to their regular pouch. … worn while eating. (Ed: Most authorities permit eating a little snack after davening, like if one intends to continue learning afterwards with tefillin.)
If someone’s tefillin fall to the floor (even in their bag), it is customary to give a few coins to tzedaka.