I should have mentioned I have an electric dryer, not a gas dryer.
In the winter I can use all the humidity (and heat) you can give me. In fact, most homes around here have humidifiers installed in their heating systems. I have a wood burning stove running in the basement, about 30 feet from my dryer and a circulation fan that blows air around the stove. My dryer vent runs near the ceiling attached to the plastic waste line from the bathroom. Attached to the vent is a stretched out leg from some old pantyhose. It acts as a lint filter and distributes the moist air a bit.
I do not have mold or mildew. My basement is wide open, no small dedicated laundry room.
In mid -spring when I don’t run my stove so often and don’t need the humidity, (April showers bring May flowers) I reattach it to the outdoor vent.
There is another advantage to internal venting in the winter. If the dryer vents outdoors, outside cold air is drawn in to make up the loss. For many months of the year that air is below freezing and needs to be heated.
@rojo Right. I can’t imagine people moving their dryer to vacuum the vents. The lint trap is easy. but pulling the condenser and vacuuming the back of the unit? No way.