Product review (5 stars): Think you don't need this? Well, you do.
First, let me admit: I didn't think I needed this tool at all, and argued with my husband about spending money on a glorified coat hanger. When the "Auto-Dry" function on our dryer started delivering me damp clothes on a regular basis, I reluctantly agreed to get this and clean out the vent.

Our dryer vents out to the side of the house, in a nearly-straight line that is no more than six feet long; it didn't look clogged from the outside, and seemed to be blowing plenty of air there, so I was skeptical about how much lint might be trapped inside. I was ultimately disgusted to see all the gunk this tool pushed through (my husband was gloating "I told you so.").

You get plenty of extensions for longer duct runs, and they are really flexible. Make sure to tape connecting sections at the junction, and turn the whole thing clockwise only---you don't want the pieces to come apart inside your ductwork. Since we had such a short run, we just manipulated it by hand; I can see how using a drill would be a benefit on long ducts though.

Whether you're paranoid about burning the house down, or you just have a dryer that isn't working so great anymore---you need to get the lint out of the duct! A bonus of sorts: disconnecting and moving the dryer gives you a chance to look for all the missing socks!