Ah yeah, been there, and probably the first time was when renaming a function but missing to update callers, so callers keep calling the old function, and you have no idea why the changes you made in the new function aren't working.

I have a this little function for clearing the current namespace that I call every time I rename any var inside a namespace:

  (defn clear-ns []
    (map #(ns-unmap *ns* %) (keys (ns-interns *ns*))))

Not a perfect solution, but personally I also don't know a better solution that doesn't involve loosing out on other (non-negotiable for me) benefits.

Couldn't you have one test that requires your -main and runs it?

Just fire that off every now and then?

Basically the same thing, but you don't lose repl state

Full test suites I run before committing essentially, in a separate tab altogether, then the full suite is typically also run in CI before any deploys.