Clean your dryer vents, even if you DON'T think you have too

I bought this dryer vent cleaning kit at my local Lowe's. I didn't plan on it but it was on sale for $25 at the checkout line. I always clean down into the dryer and did vacuum from outside. The dryer works fine and there was no airflow restriction so I thought everything was ok. WRONG!!! Watch how much lint comes out!! My vent is solid metal piping about 30'-40' long. So I still need to clean from the other side or maybe buy another kit and extend the wands. The kit comes with a vacuum adapter that I guess you can suck or blow depending on the application.