While Lightroom's backup files are self-standing catalogues, and can be run without any further fuss, they do take up a lot of disc space - until you realise how much they shrink when zipped. I've always zipped them because of this space issue, but another reason requires me to break a little confidence…. A while ago I met someone who had double clicked his backup catalogue files and had managed to get new pictures into the backups and into his master catalogue, insofar as it was possible to identify one in the hundred or so he had accumulated.

Anyway, The Photo Geek (Matt Dawson) has developed a handy plugin for zipping Lightroom's backup files:

One obvious downside of backing up is the increased consumption of disk. For example my backups for a ~10000 photo catalog are around 220Mb each. Multiply that by 52 backups a year and 11Gb of my laptop