Mormons have a strong sense of communality that stems from their doctrine and history. LDS Church members have a responsibility to dedicate their time and talents to helping the poor and building the church. The church is divided by locality into congregations called "wards", with several wards or branches to create a "stake". The vast majority of church leadership positions are lay positions, and church leaders may work 10 to 15 hours a week in unpaid church service. Observant Mormons also contribute 10 percent of their income to the church as tithing, and are often involved in humanitarian efforts. Many LDS young men, women and elderly couples choose to serve a proselytizing mission, during which they dedicate all of their time to the church, without pay.