In the past, citizens who reached adulthood had to register and were issued an "election booklet" with which they voted. Nowadays, registration for voters is not needed: it is done automatically as each citizen comes of age. Identity is proved by state-issued ID cards or passport. Special registration is necessary only for absentee voting, which is done at the place of a voter's temporary residence on election day. Many Greeks choose to retain their voting rights in their family's original home, sometimes by reason of tradition, sometimes by reason of patronage.