This varies a lot from country to country as we noticed working with a very international group of friends in Spain. My friend basically sent out an invite to

This varies a lot from country to country as we noticed working with a very international group of friends in Spain. My friend basically sent out an invite to her party with staggered start times based on nationality. Spanish Greeks were asked to come two or three hours before the real start time, French one hour and Brits and Germans were given the actual time.