When the event organiser books the venue for an event, the company that is supplying the venue to you will set you a time in which people must start attending to the venue and a time in which people myst be vacating the venue.
If an event organiser is organising a big event, he / she must work out how long they will have to remove any equipment which was used during the event. All venues will have different arrangements which tells the hosts of the event and the event organisers how the suppliers want their venue left in. Most event organisers need to leave all venues in a tidy state this is the minimum amount of work in which they can do.
Occasionally Venues ask if the event organsiser can clean u the venue once everyone has left the event, so occasionally they'll ask fo the event organisers to take some cleaning equipment.
At the end of every event, the event organiser is to look back at the accounts. By looking back at the accounts it will show the event organiser every item of expenditure that they have budgeted. When the accounts have been checked they can work out if the event has made a profit or if they have broken evan. If they have made a profit from the event they would then need to work out what the profits will go towards. For example it may be re invested into the organisation to bring more money in. Breaking evan means that they havent made a profit nor have they made a loss from the event.