When the Fab's backup starts the actual backup, it immediately shows the total size of the backup, so it doesn't seem to take very long to calculate. The total could either be listed on the final screen before executing the backup, or an optional Preview feature could display the total (and perhaps the breakdown of sizes as per the messages that are seen after the backup starts).
I agree with Diggs that this would be an incredibly useful feature. Quite a few times I've had to cancel a backup after starting it, due to the total gigabytes displayed immediately after starting.
I agree with Diggs that this would be an incredibly useful feature. Quite a few times I've had to cancel a backup after starting it, due to the total gigabytes displayed immediately after starting.