An opening ceremony usually lasts 45 to 90 minutes. The structure: 1) Reception and drinks (15 min): guests arrive and network. 2) Formal part (15-20 min): welcome address, speeches and ribbon-cutting. 3) Tour (15-20 min): guided tour of the building. 4) Extended drinks or lunch (20-30 min): networking and mingling. Too quick (30 min) feels superficial; too long (more than 2 hours) wears guests out. The ideal middle ground: 60 minutes of formal programme, with room for informal mingling before and after. For larger openings (100+ guests) you reserve extra time. For small openings (20-30 guests) 45 minutes can be enough. Live Impact plans the timing of openings precisely.