Election Obligations & Standards Database
"As a good practice, the boundaries of electoral constituencies should be examined and reviewed every ten years and, ideally, shortly after the completion of a periodic population census. "
OSCE (ODIHR): Guidelines for Reviewing a Legal Framework for Elections, Second Edition
, pp. 16-17
Guidelines for Reviewing a Legal Framework for Elections, Second Edition
The delimitation of boundaries should be reviewed frequently enough to ensure equal voting rights and account for population movements.