Man Eric, where do you live that you have vent police citing people for too long a dryer vent.
50' is a really long run. I would expect that you have to pull it apart and clean out lint at least every year. If you could answer a few questions we could narrow down the guesses.
What is the closest outside wall to your laundry room?
How many stories on the home, and which floor is the laundry on?
Is the floor a built floor or slab and are the vent pipes accessible?
Gas or electric?