Our income and expenses change often. When and how should we review the budget?

A budget is a living tool, not a stone inscription, so it needs reviewing whenever circumstances change. Review it when big changes happen, such as the birth of a child, a job change, moving house or rising prices. Even when there is no big change, a short review every few months helps catch leaks early. Compare what was planned with what was actually spent, and adjust honestly. Involve your spouse so you both own the budget. An updated budget stays useful; one left to go stale will be ignored. See family finances.