When I worked on airspace design and noise abatement procedures the rule of thumb we used is that unless there were mitigating circumstances (read obstruction) ariivals decesnded at 300 feet per mile and departures climbed at 600 feet per mile.
This figure was an average that we could use when we put lines to a map.
When we went to the public during environmental impact meetings most of the complaints we received were from landowners living within 5-6 miles from the airport. The key word is airport. That includes departure and arrival/aproach routes.
We could only tell these people that within those 5 or 6 miles there will always be the potential for overflights simply because of the number of aircraft using the airport and ATCs need to safely space aircraft and the potential for visual approaches by all type aircraft from different directions.
Outside of that 5-6 mile area aircraft would normally be at or above the minimum radar vectoring altitude and ATC would have more discretion concerning overflights.
It was a fact of life and little could be done close in to the field. They didn’t like it but that was that.
I’ve lived near airports all my life and I was always required to sign a statement before I contracted for the purchase that I was aware that I was close to such and such airport and there would be aircraft noise.