What to back up

To decide what data should be protected is the first step in developing your backing up strategy.

To choose what files to include into your backup projects consider the following aspects:

Is it easy to restore a file if you accidentally lose it? If you create an UNIQUE document (say, you're a writer and have just finished a poem), it's the first candidate to be backed up! On the other hand, you can always re-install a corrupted system file.
How valuable is the file? Imagine that you lost the file. What are you feeling? If your pulse becomes rapid, you probably need to back the file up.
How much storage space you have for backups? How fast is your system (and network)? Having a lot of free storage space, you can keep many copies of most (or even all) of your files. Having a little space, you should consider backing up the unique and valuable files at first. The size of a file can also affect your opinion of this file.
How reliable is the disk your files are stored on? All modern hard disks have the feature that allows you to be aware of HDDs reliability status. Consider obtaining a program that controls parameters of your hard disk and notify you about possible disk failures and performance/reliability degradation. Back up the files that are on non-reliable disks more often.

Certainly it's unreal to consider each file separately. We offer some more simple ways:

To select files by type. You can decide that all your documents should be protected. Or if you have not enough storage space, you may choose a number of file types to protect (MS Word .DOCs, PhotoShop .PSDs etc.). The ABE offers you to include and to exclude files by mask, so you can easyly implement your decision. The Filter Organizer (Tools / Included filters, Tools / Excluded filters) allows to configure mask filters. Remove the ones you will never use. Add new ones. Group the file-types that you'll work with identically. Say, you can add a filter "Office documents" which contains both the .DOC and the .XLS files. By configuring filters you make your work on selecting your projects masks simpler.
To select files by location. In most cases you know what folders contain more valuable files. We tend to sort files by job, by type, by cost etc., and place the same files into the same folders. When we need to save a file, we choose the folder that already contains files of the same kind. Many people save near every file to My Documents folder. So, the folders where you store the files you produce are the first candidates to be backed up. The ABE allows you to select any number of folders to be included into a backup project.
To select files by date-time. If you know that all important files are newer than a date-time and unneeded files have an older date, use the "Add only files newer than" option.
To select files by size and attributes. You may decide that you need to protect only the files matching a size interval. You also may decide that you want to include files with Archive bit set or to exclude Hidden files. The Professional edition of the ABE allows you to make the size- and attribute-based selection.

With the ABE you're free to use any combination of methods above to select files to be protected.