I picked up the habit of doing this manually a couple years ago, when my meeting load mushroomed following a reorg.

I also started getting assertive about declining meetings if I thought they were asking for too much time. Too many folks were in the habit of reflexively blocking out a full hour for a decision that could be made in 15 minutes plus a briefing email that everyone could be expected to read ahead of time. I was surprised to find that that one didn't really burn any social capital. Far from being offended, many of my colleagues thought it was a good idea and started following suit.