One of the best reasons to use sparse bundles is because they can grow and shrink in size without taking up more space on the disk than the data they currently contain. I'm curious why, when making a new blank sparse bundle disk image in Disk Utility, there is the "Size" field? I made one with the size set to 100MB and, sure enough, trying to copy a 1GB file into it failed. OK, so is there any drawback to setting the size huge, future-proofing yourself? Can I just set the size to 10TB and forget about it? Is there a way to edit the size of an existing sparsebundle file so it can grow past what it's initial size was set to?