The Importance of Contact/Housing Retention

Connectors retain their electrical contacts within an insulating housing. Some retention mechanisms are more reliable than others. Serious issues can arise if the contacts are not assembled properly, or if the design of the retention device is not robust. This paper focuses on user-installed contacts, and addresses the importance of design, materials, handling, and other factors that assure good contact / housing retention.

http://www.connectorsupplier.com/the-importance-of-contacthousing-retention/