This is a nice trick for running your 30 minute meetings. I found it during listening to the latest episode of The Engineering Commons. 30 minutes are the standard slot for a meeting it seems. So plan for a 30 minute slot, but plan to run the meeting in 22 minutes. Why? Because if you are in a series of meetings, chances are that you’re going to be on time only in the first one (and even that is debatable). So delays accumulate and you can forget ever making it to the last meeting.
So why 22 minutes? My guess is that if you have planned for 5 meetings in a row, this 22 minute window slides enough within each 30 minute slot so that you can make it in all of them.
For longer meetings you can always multiply appropriately.