You should arrive

* At the exact time specified – for dinner, lunch, or appointments with professors, doctors, and other professionals.
* Any time during the hours specified for teas, receptions, and cocktail parties.
* A few minutes early: for public meetings, plays, concerts, movies, sporting events, classes, church services, and weddings.
If you are invited to someone's house for dinner at half past seven, they will expect you to be there on the dot. An invitation might state "7.30 for 8", in which case you should arrive no later than 7.50. However, if an invitation says "sharp", you must arrive in plenty of time