The benefits of breastfeeding are many.  They include; nutritional; immunological; cognitive; decreased morbidity and mortality; analgesic effects; decreased costs (products, healthcare); decreased risk of allergy; and improved jaw development and dentition. Exclusive breastfeeding is recommended as the best form of feeding in the first six months .
60% of mothers who cease breastfeeding do so earlier than desired.  There are numerous reasons why mothers cease breastfeeding. These include maternal and infant factors, as well as societal and environmental factors.
Infant related factors are important reasons for breastfeeding cessation with reported trouble sucking or latching (26%), self weaning (26%), nipple problems (20%), pain (15%) being significant contributors. 
These infant factors may have a secondary effect on other important factors such as perceived milk supply, perceived satisfaction, maternal pain, maternal confidence, and desire to continue. For example, studies have shown that milk stasis is the primary dysfunction in mastitis, and that attachment and side preference is the most significance contributor to milk stasis. 
(Copyright Adam Stewart, 2014)
1. Leung, A. and R.S. Sauve, Breast is Best for Babies. Journal of the National Medical Association, 2005. 97(7): p. 1010-1019.
2. WHO, The Optimal Duration of Exclusive Breastfeeding, Report of the expert Consultation of the Optimal Duration of Exclusive Breastfeeding, Geneva, Switzerland, March, 2001.
3. Odom, EC et al. Reasons for Earlier Than Desired Cessation of Breastfeeding Pediatrics 2013;131:e726–e732)
4. WHO, Mastitis; Causes and Management, Department of Child and Adolescent Health and Development, Geneva, 2000