Decide how long the meeting needs to be, ensure it starts and finishes on time, and hold everyone accountable for time discipline. Just about every leader says they are very busy and yet they are often prepared to allow people to arrive 5 minutes late. For a 30 minute meeting, that's a waste ratio of 17% (for everyone who is kept waiting). Would anyone accept a 17% financial penalty that could be easily avoided? Then why accept it when applied to time, one of the most limited resources? Also, I'm a fan of Office 365 for business and I like the Outlook calendar function. However, the default time it offers for new entries is 30 mins with 30 min increments. That makes it easy to set meetings for 30 mins or an hour, say, even if the time required is shorter. Overriding the defaults and entering specific times could save you even more.