What is the proper length for a meeting?

What is the proper length for a meeting?

Seventy minutes is my idea of how long a meeting should go. It's a good time to give what I call a biological needs break, for people to go to the washroom, or so they can pick up their cell phones. Remember we are addicted to technology, it's an addiction that we need to check that cell phone, we need to check our e-mail to see if anybody's looking for us. So seventy minutes is a good length of time to hold a business meeting, so they can then get back and you can have sandwiches brought in and you can have fruit or something to get people's blood sugar back up, so that they can continue to participate in the business meeting.