Now, the one time I cannot cope with is the amount of time one is supposed to the fashionably late for a general party. If the invitation says 8 PM, there is supposed to be an 'undersanding' that the host will NOT be ready at 8.... those who 'know' seem to arrive anywhere from 20 minutes to an hour or more after 8. I DO recognize that then are 'certain' people who consistently arrive 10-30 minute EARLY, and one does not wish to be the only ones there to interact with them, as there are often other eccentricities coupled with earliness. Would it be impolite to be very specific in the invitation?