When is the last time you defragmented your hard drives?  Perhaps you have set yourself a reminder to do it once a week, or month.  You may have purchased something like Diskeeper, and this problem is taken care of automatically.  There is also the possibility that you do not know how to defragment your hard drives.
Traditionally, the built-in defragmentation tool for Windows was used for once and a while runs, or when one remembered to do it.  A few commercial tools took note of this and created their line of software tools to automate the process.  Microsoft has since added the ability to create or change a scheduled defragmentation run, through the Windows graphical user interface, in Windows Vista and 7.
The long and short of Windows defragmentation is that your defrag runs begins, and then you go do something else, away from the computer (with the exception of commercial software designed to run in parallel to normal Windows operation).  This is easily accomplished if you have it set to run late at night, or manually start the process before you are off to bed.  But what if you had more control over your defragmentation, without the cost of commercial software?
Defraggler (found here) comes across as a happy medium between the Windows defragmentation tool, and commercial grade software.  Though it does not run constantly in the background, if offers functionality above the Windows utility.  Though the main graphical view for Defraggler has the standard Analyze and Defrag buttons, the display yields more information than the standard Windows view.

Defraggler does show the information about your computer’s hard drives.  In the main display you can see Used and Free space, and Fragmentation levels (expressed as how fragmented your drive is, by percentage), if an analysis was run.  Additionally, the main screen has an area displaying capacity, of the currently selected drive, in pie chart format.

So we now know that Defraggler can do the standard defragmentation fare.  But what sets it above the Windows built-in tool?  Defraggler has the ability to narrow down a defragmentation run to a single file.  Windows will give you a “post game” report of what files had the most fragments, but Defraggler can target these files after an Analysis is completed.
In the above screen shot, Defraggler shows a list of fragmented files, sorted from the ones who are heavily fragmented down to the least.  You can do two things at this point.  You can click and select the box to the immediate left of the Filename column heading to select all of the listed files, or click to select individual files; and then click on Defrag Checked at the bottom of this screen.  Doing so will save time parsing the entire hard drive, and focus on only the files you chose for defragmentation.
One also has the option of looking at blocks of files, after an analysis is completed.  From within the colored block display, you can hover the mouse pointer over an individual block of files, and click to select it.  A small message will appear next to the block telling you how many file are contained in this area.
After you click to select the block of files, the file list is shown in the lower portion of Defraggler’s graphical display.  This view is similar to the individual files list mentioned earlier.  Instead of going over all fragmented files on a particular drive, you have now whittled down the list to one block’s worth.  You have the same options again with selecting all or individual files for defragmentation.
Besides defragmentation of regular files, Defraggler can perform an error check on a drive and defragment free space.  Why defragment free space?  This helps control fragmentation of newer files.  If you look at it from the perspective of a book shelf; does it seem practical to put new books on a shelf wherever random open spots are, or where a larger open area is for placing new books one right after the other?  This is just one more advantage that Defraggler has over the tool in Windows.
Like newer versions of Windows, Defraggler has the ability to scheduling within the graphical user interface.  To get to the Schedule section from the main window, you click on Settings, then Options; and then the Schedule tab.  Here you can choose which drive you wish to defragment, how often (Daily, Weekly, etc.), a start date, and what time of day.
If you can afford commercial grade software that allows an optimized defragmentation routine running alongside normal Windows operation, by all means.  If you are tightening you belt like many of us, and in need of utility to help with hard disk fragmentation, then you should consider Defraggler.