I think a lot depends on where you are going, what you are seeing, and how experienced you are.
In 2004, I spent 12 nights in Germany, seven in a town in the Black Forest, five on the middle Rhein. Both places were bases for travel to neighboring towns. From my base in the Black Forest, I made two trips into Karlsruhe to work in the Baden-Württemberg archive, visited two spas and a handful of nearby towns. From Boppard, I visited Bacharach, Oberwesel, St. Goar, Koblenz, and Brauback - all easily accessible by the frequent trains along the Rhein.
Three years later, I toured the Romantic Road. Between Oberammergau, where I spent 2 nights and visited Linderhof, and Würzburg, where I spent 2 nights and saw the Marienberg fortress and the Residenz, I spent five days exploring towns on the Romantic Road. I visited eleven venues; Wieskirche, Schonau, Landsberg, Donauwörth, Harburg, Nördlingen, Dinkelsbühl, Feuchtwangen, Rothenburg (briefly, I'd been there twice before), Weikersheim, and Bad Mergentheim, staying overnight in four of them. On most days, my travel was just a few hours, with most of my time in the towns. For this trip, I relied heavily on skills, such as how to pack light for efficient movement, that I had learned on five previous trips.
What I'm trying to say is that it depends on how much there is to see in the towns you visit and the time to get between them. What I don't understand is trips where someone spends a day (2 nights) in a town with far more to see than you can in one day, alternated by all day travel to the next venue.