I've lately been using LLMs to do a lot of testing and verification.

An LLM can go and pull files off NFS, and write and run verification scripts in less time than I can even think of a testing strategy or locate the files.

Sometimes they'll do it unprompted

For writing unit tests, which are often repetative and verbose, they are another godsend.

Overall they're freeing up a lot more time for nice things like thoughtful API design, refactoring, system architecture and design work etc.

For exploring massive codebases they are another godsend