I've got 2 drives. An internal and an external. My internal drive is a 256GB SSD which isn't a lot of space when you shoot 12MP and occasionally 31MP (when I get my H3DII-31 back someday...).
I usually keep the stuff I "need" on the internal. When I'm done with that folder, I'll move it to the external as an archive. Lately, I've noticed that my disk space hasn't increased much by moving these folders off-site. I couldn't figure out why. I figured my pictures were the only things taking up space... boy was I wrong.
I began investigating. I started at the root level and found that most of my space was being used by the folder "Users"
I scratched my head because I knew that my "Desktop" folder only used 8GB and my "Pictures" folder only took up 20-30GB. So I rummaged through each folder until I found this:
And within Lightroom the biggest offender was this:
Just how big of an offender are we talking? This big:
Between 2 screens I couldn't show you how many backups I've made. It dates back to June 9, 2009. The truth is I use another external just for Time Machine and this article says you really don't need Lr backups if you're doing routine backups of your entire HD. So I deleted all the backups except for the most recent 3.
Now I've got this (oh and I cleaned out the trash can):