To me, it completely depends on the gun. I have had some that out of the box needed an action job because they were out of time, mainly less expensive revolvers. Others, I just did a detial strip and cleaning, reassembled and have shot ever since. Then there is my 1897 which is still not good to go, but it was a box of parts when I got it for half of a song
.
I actually had an action job done one time that made my Rossi soooo smooooooth, but it didn't last 2 more years of regular CAS competition. This taught me to follow the old adage "If it ain't broke, don't fix it!"
Now, My Norinco 1887 needed
some work to make it function reliably, but that has proven to be the exception, not the rule.
On the other hand, knowing that your equipment is capable of being extremely accurate, smooth, and reliable gives you a great deal of confidence. Again, this is from experience.