To new Mac users, the Downloads folder is quite confusing and even "invisible." As a Mac consultant, you wouldn't believe the number of times I've found multiple copies of downloads, updaters, and pictures in the Downloads folder -- all taking up valuable room on your disk.
Reader Joe Delk brought this to my attention recently and thought it would make a great Mac 101 post. Joe said "My harddrive has filled up recently and even after deleting most of the movies, iTunes or otherwise, it was still a struggle finding enough space for new movies and new programs. One day last week I had the epiphany of deleting everything in my 'Downloads' folder older than six months (I've had this MBP for around 2 years). It immediately freed up 18 GB. I was astounded. And I haven't missed anything since. Even after going through the recent stuff, I found that I had downloaded some items three, four, ten times, adding much additional space."
I'm personally pretty good about cleaning out Downloads on a regular basis, but when I did my cleaning today, I was able to toss 3 GB worth of unneeded files. Many Macs have a Download folder icon in the Dock, usually on the far right side near the Trash. If you don't have that icon, the easiest way to jump into the folder and start tossing things is to click on your Mac desktop, then select Go > Downloads from the menu bar.
Fellow TUAW blogger TJ Luoma pointed out one of his favorite ways of saving space on Macs. It's a relatively new app called Spacie (US$1.99) that's available on the Mac App Store. Spacie lists files by size or location along with their sizes, making it easy to see where you may have duplicates or large unwanted files that can be deleted.
Cleaning out the Downloads folder can be very helpful whether you have a new Mac with a smaller drive (like a MacBook Air) or an older Mac that's losing space. Be sure to remind yourself to clean it out often.