Be Aware of the Makefile Effect

Make and Makefiles are incredibly simple when they are not autogenerated by autoconf. If they are generated by autoconf, don’t modify them, they are a build artifact. But also, ditch autoconf if you can.

In the broader sense: yes this effect is very real. You can fall to it or you can exploit it. How I exploit it: write a bit of code (or copy/paste it from somewhere). Use it in a project. Refine as needed. When starting the next project, copy that bit of code in. Modify for the second project. See if changes can be backported to the original project. Once both are running and are in sync, extract the bit of code and make it into a library. Sometimes this takes more projects to distill the thing into what a library should be. In the best case, open source the library so others can use it.

They are simple but very often wrong. It's surprisingly hard to write Makefiles that will actually do the right thing under anything other than "build from scratch" scenarios. (No, I'm not joking. The very existence of the idea of "make clean" is the smoking gun.)