It is sadly not widely known that there are two ways to shorten default meetings for Outlook:
With Office365, it’s just a few clicks away:
Settings > Calendar > Events and Invitations >
1. Select File > Options > Calendar > Calendar options.
2. Check the Shorten appointments and meetings checkbox and in the dropdown box choose End early or Start late.
3. Use the drop-downs to select the number of minutes for events less than one hour and one hour or longer, then click OK.
We’ve heard a common complaint/objections that “well, meetings will just run to the top of the hour anyway” (or equivalent). While this may be true at the start, as a meeting organizer, you have the ability to affect and steer the change gradually. Having a meeting begin a little after the hour / 1/2 hour or end a little early is a subtle but effective behavioral priming signal.