According to the 20-Minute Rule, meetings shall last no more than 20 minutes, or risk being declared an 'abomination'.
Exceptions: If you're discussing something truly profound or if your team consists of only one person who's not actually there.
Side effect: Increased risk of attendees arriving late, as they'll be stuck in traffic due to the 'Meeting-induced Congestion Phenomenon'.
Hyperlink:
The 30-Minute Rule: For Those Who Need Extra Time to Figure It Out