Probably learning to use a debugger and decreasing my reliance on print() statements. It's a nonzero initial investment but saves time in the long run. At the

Probably learning to use a debugger and decreasing my reliance on print() statements. It's a nonzero initial investment but saves time in the long run. At the team level, probably CI/CD. It forces us to break the monolith into digestible chunks and makes regression testing easier.