Does my code still make sense to me 6 months later? Did I introduce new bugs? Are people using my building blocks to add features or working around them/ redo

Does my code still make sense to me 6 months later? Did I introduce new bugs? Are people using my building blocks to add features or working around them/ redoing them? These are not good metrics. I have researched this and it seems there is no good way to measure coding improvement except subjective measurements.