If you want more immediate and automated alerts about changes that your collaborators are making, rather than finding out by reviewing the revision history, you can turn on Google’s notifications.
Open your Tiller Sheet
Open the “Tools” menu
Select the “Notification Rules” option.
In the “Notify me at...” selection you’ll want to choose “Any changes are made” and from the “notify me with” setting you can either get a daily digest or get an email right away.
The email will indicate who made the change and includes a link, which allows you to quickly access your Tiller Sheet.