Noise barrier wall - does it help?

Regarding habituation, I share my experience - this is not objectifiable: How quickly one gets used to noise is individual. I grew up in a house under the flight path to Düsseldorf Airport. You could see the landing gear being extended. A conversation in the garden was briefly interrupted when the plane passed by. I only consciously noticed the aircraft noise when we had guests. It was that normal for me. We have been living a few kilometers further away since 2001. Objectively, it is quieter, and I usually do not consciously hear the planes. My wife comes from a quiet area. For 18 years, she has regularly woken up to the first plane and only finds peaceful sleep after the last plane. No habituation. A quieter location was therefore a deciding factor for our house currently under construction.

Regarding the subconscious, I share my conviction (there are studies that would support every answer): Noise is unwanted sound. If we consciously perceive this noise, we feel more or less disturbed - this is individual. The volume of a sound is therefore not decisive for the degree of disturbance. Have you ever been annoyed by a dripping faucet? Natural sounds such as the rustling of a forest or the roar of waves are apparently not perceived as noise by humans. Noise is like a baseline load. The sounds are processed - whether consciously or not. Humans need regeneration - sleep. A baseline load during sleep reduces the efficiency of regeneration. In the long run, this cannot be healthy.

My conclusion: It must be quiet at night. During the day, one can manage quite well with a certain noise level. I would no longer buy a house or property with noise at night. Although aircraft noise usually pauses between 11:30 pm and 6:00 am (night flight ban until 10:00 pm), depending on wind direction, we hear either the motorway or the highway (about 500 or 1000 meters away as the crow flies).

You should definitely clarify in advance whether such a wall is even allowed. You can't just put a 2.5m high wall next to a street. Hopefully, you know roughly the other restrictions you are subject to in the outdoor area? Noise would be my least concern with the property.