Our laundry dryer is vented to the outside through the shortest possible path, a 4" through the wall vent located directly inline with the dryer's exhaust outle., Its "pipe" protrudes from the inside wall by only about 1".
An 18" long piece of aluminum foil/coil spring vent duct allows just enough room to move the dryer away to tighten the hose clamp joining it to the vent.
Last week I noticed that the plastic outside part of the vent was bulged out and cracked and two of its three louvers had sailed off into the sunset.
Seems like someone had pushed the dryer against the wall hard enough to force the "pipe" to bust the plastic on the outside, which was brittle as glass after nearly twenty years of exposure to New England weather.
I was pleased to find an *identical* replacement at ACE Hardware, and a bargain at only $2.98. The plastic parts looked like they'd been shot in the same mold as our old one, and the four mnounting screw holes lined up perfectly, but I'd bet that the mold is now located in a factory in China.
The point of all this is that before calling the job done I measured the "safe distance" between the back of the dryer and the wall, ripped a two foot long piece of 2 by 4 down to that dimension and laid it on the floor behind the dryer. If you have a similar venting setup you might consider doing the same.
Jeff