I'm sure you've tried renaming files the way most of us have: one at a time.  It's tedious, so you don't even bother messing with it most of the time, even though your mp3 collection is in complete disarray.  Yeah, I've been there.  I know where you're coming from.

I absolutely LOVE this program.  It allows you to view directory (folder) listings as text files, meaning you can edit lists of file names as easily as navigating a document.  (In other words, no more click to highlight... click again to edit... click again to put the cursor in the right spot.)  You scroll around like you like.  You type what you want.

More impressively, you can use many of the same tricks as you would such as copy and paste... something with obvious advantages for mp3 tracks from the same album.  A lesser-use but arguably more powerful text tool is search and replace, something that can even fix case-based errors such as inconsistent capitalization.  Maybe that's a bit OCD, but I wouldn't have found this program to begin with if I wasn't.

Finally, since you are viewing the file names as text, you can generate lists of the contents of directories.  This is especially convenient if you want to share information about which files you have and/or are missing.  My previous attempts to do this have included clumsy screen captures, time-consuming transcriptions, or DOS-based directory listings that often truncated names and contained extraneous information about file sizes, last date modified, etc.

I finally cleaned up a decade's worth of inconsistent file-naming conventions in my mp3 directories in about an hour.  Without this program, it would have taken days to do and probably another decade for me to have gotten around to.  As a result of the organizing, I ended up deleting a number of redundant copies of tracks that sat on my hard drive for years.  From there I moved on and converted my home video file name format to something more intuitive (i.e., 200803181354 became 2008-03-18_01_camping trip).

Maybe you aren't as OCD as I am, but if you have any such drive to clean your directories up, then this is the tool to use for it and, oh, you’re welcome.