Is your Mac running low on disk space? All those apps, MP3s, photos, and videos that you synced from your old iPhone add up over time. You could look through each folder on your computer and hunt down all your large files manually, or you could download WhatSize, by far my favorite tool for viewing and managing disk space usage on a Mac.
WhatSize is incredibly simple to use. Click on a mounted drive and it will show you the size in bytes of its subfolders, sorted by size with the largest files first. Your default view is similar to Finder, with other view options available such as a table view and pie chart.
Another handy feature is the ability to find duplicates within your folders. Click on a mounted drive, and then select the "Duplicates" icon. This will create a list of duplicate files with the ability to delete the unwanted copies from your hard drive.
Once you've cleared out all those large files and removed your duplicates, click on the "Cleaner" icon. Cleaner will show you extra bits of data that you can erase to save room on your hard drive. On my last clean, I had over 21GB between my Downloaded Files and Cache Files alone.
If you followed the steps above and still don't have enough room on your hard drive, head over to Itemcycle and sell your MacBook. You can use that money toward your new laptop purchase!
WhatSize is available as a free 30-day trial with a purchase price of $29.99 on Mac only.