I spent some time today moving some photos to a backup hard drive. Then I was trying determine why my MacBook Pro (500GB storage) had so much space devote to pictures. I went through each folder in the Pictures directory and found 50 GB of memory in the Lightroom folder. Upon further inspection, I saw that each backup over the last three years was still there. THAT IS NOT NECESSARY. So I deleted (moved to the trash can) all the Lightroom Backups except the most recent one. Then I emptied the trash can. Each photo I store is over 30 MB. That can really add up. I certainly need to do a better job of deleting old photos and duplicates. And really watch the panorama shots. I had one that was over 500 MB! And of course video can really use up a lot of memory in a hurry. The Adobe website has more info on backups.