Good for you talking with your neighbor. 20 is a good number though there might be a few more; however during the Cold War we had over 200 posts in Germany. The 3d Armored Division alone was divided among a dozen kasernes (barracks) in a half dozen towns. Everyone of those is now closed and a few have been totally demolished.
Here is a Wiki article on US bases in Germany in the 1980s and now. It is fairly accurate as best I can tell: https://en.wikipedia.org/wiki/List_of_United_States_Army_installations_in_Germany
The strength of US Army Europe in the 1970s and 80’s when I was there was about 250,000 soldiers. And several thousand more USAF airmen should be added to that number.
Deutsche Welle has this article about current us military locations and personnel number in Germany: https://www.dw.com/en/us-military-in-germany-what-you-need-to-know/a-49998340
I spent 7 of my 20 years in the Army stationed in Germany and then another 22 years as an Army historian and archivist. I’m glad that the Cold War ended and that we’ve been able to bring nearly all of our troops home, but realize that a presence is still needed there as a member of NATO and to support the new democracies and republics in the former Warsaw Pact countries to give them support against a resurgent Russia, which we are seeing under Putin.
I will admit that it irks me that there are folks here on FR who do not know/realize that the US no longer has its Cold War presence in Germany of 7 divisions in 2 corps.
The half dozen main base areas are primarily logistical support and training areas that are way stops to a possibly new Cold War II border with Russia. Germany shrunk its military to get a peace dividend after 1993. It is no where the militaristic nation that we see as an almost stereotype for the mid 1800s through the end of WWII. I venture to say that we over succeeded in pacifying the German people.
This major was primarily stationed around the Pacific rim, although he spent a short stint in Europe after he got out of college.
Told me that of all the places, he hated Korea. Did not care for Germany either.
Had two brothers who also spent some time in Germany-one during the late 50s and the other just after the Cuban Missile crisis. Both were eager to see Germany and came back disappointed. Not because of the country, but because of the arrogant attitude of some of the people-France also. The one in the USAF said that the best time he had was in England. Being a typical serviceman, he loved the pubs in England.