Time Machine Backing Up Large Amounts of Data Each Time

Solution 1:

On Lion you can use tmutil to compare Time Machine backups:

sudo tmutil compare                      # compare computer to latest backup
sudo tmutil listbackups                  # list available backups
sudo tmutil compare <backup1> <backup2>  # compare two backups from backup list

This should give you a good idea about where the volume is coming from.

Solution 2:

Also:

tmutil calculatedrift machine_directory

gives you an overview of the sizes differences between each consecutive backup.

It is useful to pinpoint when exactly that happens, and which backup you should compare with:

sudo tmutil compare <backup1> <backup2>