This paper reports the results of a study to understand why some New Zealand dairy farmers are changing from twice-a-day (TAD) to once-a-day (OAD) milking. Increasing herd size, unavailability of suitable labour and changing lifestyle expectations from farmers and their staff have led some to explore OAD milking as a means of alleviating these issues. A convergent interviewing process was used with 21 dairy farmers who had all adopted OAD milking. A marketing approach, based on consumer behaviour theory and farming systems theory, was used to classify farmers into segments based on their different reasons for adoption. Six segments were identified, viz., herd expansion, time needed to build capital, decreasing labour, increasing labour flexibility, feed shortfalls, and herd health, motivating farmers to adopt OAD milking. Farmers in some segments such as herd expansion and feed shortfalls indicated that they were less likely to be long-term adopters than those in the other segments. Farmers interviewed unanimously understood that OAD milking led to reduced milk yield but were generally prepared to tolerate this to achieve their short-term or long-term goals. (Contains 2 tables and 1 figure.)