In 1988, on my first self-planned trip to Germany, I bought a German Rail Pass, $160 16-day, and I'm sure it paid.
Twelve years later, I came back to Germany and bought a German Rail Pass, also for about $160. I believe it was a flexi-pass for about 6 days. When I came home, I looked up the price of all the trains I used, and I found I just barely came out ahead, but I could have saved money with a few less expensive, slower trains. Since then, as I have learned how to use the Länder-Ticket and advance purchase tickets, I have never been tempted to get another rail pass. I always save money with individual tickets.
Case-in-point: In 2017, two of us spent 20 days in Germany, with 6 major days of rail travel (arrival, 4 changes of venue, departure) plus two major excursions. 8 days. We spent $308 on one Savings Fare, 3 regional passes, 2 Verkehrverbund passes, and 2 local tickets, all for two people. German Rail only sold GRPs in 7 and 10 day versions. A seven day twin pass plus the least expensive single day would have cost $657, so I saved half by not buying a pass.
Now, admittedly I tend to travel shorter distances with local and regional passes, but even so, 8 times my longest day of travel, 6½ hours, would have only cost $442, for 2.