When to send event updates

RSVP resets

Changing an invitation after you have invited guests causes trouble:

• Date and time changes may cause meeting conflicts. Your guests may have to reconsider your invitation.

• Location changes may cause travel plans to shift, or make the meeting impossible.

• Other changes (such as an added agenda item, or more guests) may not really be changes at all).

Google Calendar now has to decide what to do.

These fields cause RSVP resets

Only two fields cause RSVP resets:

• Start time/date/timezone

• Recurrence

No other field will cause RSVP resets, even some that you would think might require guests' consent:

You're moving your event to another city? That is okay. Making it 8 hours long? Done.

You probably will want to update your guests out of courtesy (more on that below), but their previous answer continues valid.

Updates are not required

Contrary to popular belief, you never have to send updates to your guests. Ever.

All event changes take effect on people's calendars immediately, without sending updates. Updates are optional.

You technically do not even have to send invites. Yes, you can be the person whose invites just pop up on others' calendars. You may not be popular, but it's a way to stand out.

The update may be unnecessary

As stated above, you do not need updates. Err on the side of less updating and help reduce Calendar spam.

People will not read your update

Mails with Calendar updates are hard to read. All updates seem equally important. If you're like me, you open them, look if you have already accepted, mindlessly accept again, archive.

Also, your guests expect that your event respects their time (except for big events or if you're their boss). They will not bother reading updates and assume you did your homework in exchange for them giving you their time.

So the question becomes: Should you send an update? Here when I send an update:

• Changes that cause RSVP resets.
  It's good etiquette to send RSVP resets. People may miss the meeting or fail to prepare for my change, and look badly in front of others if I do not warn them.

• Changes I want in my guests' faces ("I updated the meeting description with the agenda, please read it!").
  I actually prefer chat rooms and other channels to this method.

Do not blindly hit "Send" - try to add a message to your change, it's kind to your readers. Calendar updates are hard to read, one needs to decipher what actually changed. If in doubt, do not send an update.