Attending the Anniversary Party.
Formal parties start at the time indicated on the Invitation especially if they are a serviced event e.g. in a restaurant or a reaffirmation service, so ensure you turn up at the stated time.
If the celebration is an informal event then there is some leniency on the timing however if you turn up extremely late then you may have missed any speeches or presentations that may be planned.
Open House events are just that, turn up any time between the hours stated but not outside the times.
Do not take any pets with you to the event unless specifically asked to!
If you are attending an informal party and plan on taking a bottle understand that this is a gift for the host thus make sure either it is something you know the host likes or something you would like to receive as a gift, not the bottle that was given to you last time you had a party which you hate.
Anything that requires the use of a mirror (e.g applying make-up) should be carried out in the toilets.