Common mistakes include leaving legal notice and document requirements too late, forgetting to set a realistic budget, and paying deposits before checking cancellation terms. Couples also often overlook guest dietary needs, transport, accessibility, insurance and the practical jobs needed after the ceremony, such as updating names or beneficiaries. Keep one shared checklist with deadlines, named responsibilities and a contingency fund, and confirm key arrangements in writing. Check the official GOV.UK guidance for marriage notice requirements, and consider professional advice for complex legal or financial arrangements.