This message on renting a venue is coming from a recent experience. I hope after reading this info., you will not experience what a recent client of mine went through.
Let me first start off by saying, take the recommendation(s) from your planner about a certain venue, vendor, etc; they usually have past experiences.
When renting a venue, besides from your start and end time, which should be in the contract; also clarify when you can have access to the venue to set-up for your event. The set-up time will be determine on how big an event and the level of decor planned for the venue. This should also be in the contract.
Get the name of the contact person for the venue, who will be assisting or working the day of your event. This is a critical component, in case of an emergency, spills, monitoring or adjusting of the lighting, etc.
Last but not least, make sure the venue is cleaned prior to arriving and setting up. Your set-up time should NOT include when the venue is being cleaned. Also, clarify if there is another booking on the same day and the time. If there is, make sure the time the venue will be available to you is what is written in the contract.
Now, with all that info., go ahead plan and enjoy your special event.