Swapping out an old Broan in St. Charles, Illinois for a new Airmaster today. We had to correct a sloppy install in order to optimize the performance of the new unit. We see this all too often. Using the incorrect fitting and excess piping can greatly reduce efficiency and increase likelihood of clogs.
If you hire a cleaning service do they use your vacuum or bring their own? If they bring their own ask yourself what germs, bacteria, or other contaminants are they bringing into your home from the previous 20 houses they cleaned before yours? Always better to own your own vacuum and have them use it.