I often read that German tanks were "over-engineered" in WW2. What exactly does this mean?

 Here’s a good chart that shows how much money the Germans spent on their tanks during WWII:

The Germans built FANTASTIC tanks (can you tell that I’m a fan?), but they were engineered within an inch of their life; as you can see, even the lowly Panther cost 50% more than a Sherman, and that was the CHEAP German tank! They were marvels of 1940’s engineering technology, but for a piece of equipment that is DESIGNED to (eventually) be destroyed, the Germans spent too much time and effort on their tanks (and just about everything else, too).

And, as Felix Lu stated down below, Shermans (and most other Allied tanks) were MEANT to be repaired in the field; if one broke down, you fixed it wherever it was at, and kept going. The Germans, on the other hand, would normally ship the WHOLE TANK back to the factory if something really serious broke; there are pictures on the internet of various German tanks in the process of being remanufactured back in Germany, after they broke down in the field and couldn’t be (economically) repaired in place. If it was something simple, like a roadwheel or an exhaust pipe, then they could fix it in the field; but replacing anything else (especially the internal components, like the transmission and the final drives) was a PITA, and usually required sending the entire tank back to the rear for repairs.

Source/Credit: Kelly Pedron (Quora)