You might not think much about what happens to your clothes when you put them wet into the dryer and then pull them out dry. The wet load of clothes you put in the dryer can contain about a gallon of water, and that water needs to go somewhere. This is done through a dryer vent. Ideally, your dryer vents out through a duct leading to the outside, but unfortunately, this is not always the case. In some homes, a device is used to catch the lint but releases the hot humid air inside. Since many have their dryer in a basement where there is little air conditioning, this could lead to moisture damage.
Even if the vent leads to the outside, it is important that it is located at least 3 feet from doors and 10 feet from an air conditioner unit.
Any sharp turns in the vent could lead to lint buildup, which could be a serious fire hazard, so to avoid that, the vent should be as straight as possible.