A folder with fewer files in it will open faster than a folder with lots of files. It simply takes your Mac less time to obtain the information and offer it to you if there’s less data to locate. It also takes longer to browse through a folder with many files in it to find the file you actually need. A folder (or subfolder) that is 650 MB less in size or can easily be burned to a CD. A folder that is 100 MB or less can easily be backed up to the iMac storage area on Apple’s Internet servers (if you have a MobileMe account). For these reasons, it is generally a good idea to keep folder size to a respectable limit.
If you want to find out how big a folder is, perform the following steps:
1. Open the folder to check.
2. Choose View>List View.
3. If the sizes are not already listed, choose View>Show View Options, and select Calculate All Sizes and This Window Only. Close the dialog box.
4. You can now calculate how large the folder is. (You can click the Size tab to sort by size.)
5. When finished, choose View>Show View Options, and deselect Calculate All Sizes. (Leaving it checked only makes your Mac have to work harder than it should each time the window is opened.)