I've got 2 time machine drives. I have one at home that gets used on the weekend and another that gets backed up to during the week. I recently replaced the one at my office. The only thing that is weird is that it's backing up 3-4GB of data each hour. It goes super quick, so it doesn't feel like its actually backing up that much data, though. I've ran disk utility on the disk and it doesn't find anything. Any thoughts? Is it just something weird or is there a problem with the drive?
On Lion you can use
This should give you a good idea about where the volume is coming from.