Study UX over time.
A prototype of the product is given to participants who agree to use it for 6 months to a year, and report their experiences and emotions at short fixed intervals in the form of journal entries.
Gives a good idea about the user experience in a variety of settings
High dropout rate?
Requires working prototypes
Problems with self reporting?
References describing the method
Diary method: Bolger, N., Davis, A., & Rafaeli, E. (2003). Diary methods: Capturing life as it is lived. Annual Review of Psychology, 54, 579–616.