In Munich (as in many other German cities) there are two different systems: S-Bahn, managed by DB (the national railway operator), and U-Bahn, that is your standard subway, managed by a local company (MVG in Munich).

The S-Bahn in Munich has only one track in the city center, so there are trains every 3-4 minutes, 20 minutes is on the outskirt.

U-Bahn has a 10-minute cadence in the outskirt, and 5-minute on rush hours: in the city center 6 lines become 3, so in there you have 5-minute cadence, and 2.5-minute in the rush hour.

I live near both stations, S-Bahn is the quicker way to go to my office, but being the station in the outskirt, I need to know when trains are coming.