Slightly similar lesson I learned when developing games (and other 3d apps). Make sure your debug-output is so good that you don't have to start the debugger before you already have an idea what's going on. Simple stuff like - your 2d and 3d cursor positions can be printed on screen always. You can add lines and polygons which are visible for debugging in your code with a single line (and you only comment them out afterward and don't remove them as you will need them again). When developing things like A* - make sure you can print every value on screen easily. Adding all those kind of easy debug-outputs is usually worth it over and over again and still it often only gets added to a project after people get stuck on the algorithms for too long. So right problem in 3D-development: debug output first.
If/then guards are better than commenting out code, so you can toggle debug at runtime, or hardcode a constant to get an optimized production build that skips the if-check.
You need both. The thing with easy debug-output is that you start using it so much that you simply get too much stuff on the screen at the same time if you keep it all enabled.
