Talking with a fellow about dryer vent cleaning, he said his residential dryer vent was cleaned two years ago, and his dryer was still drying laundry ok.
I replied that A Lint Free Vent recommends getting your residential dryer vent cleaned at least once a year. Commercial dryers or dryers in homes that do a lot of laundry can need more than one dryer vent cleaning each year.
I offered to clean the guy’s dryer vent, and if not much lint came out it was free, but if a lot of lint came out, he owed me.
He accepted my challenge and said to go ahead, clean the dryer vent.
After he saw all the lint coming out of his dryer vent, he just turned around and started writing me a check.