HOW?  Use tools like clouded glasses and weighted gloves to experience processes as though you yourself have the abilities of different users.

WHY?  This is an easy way to prompt an empathetic understanding for users with disabilities or special conditions.

(e.g.  IDEO designers wore gloves to help them evaluate the suitability of cords and buttons for a home-health monitor designed for people with reduced dexterity and tactile sensation.)