Pro tip: check your collet nuts before blaming the machine
I spent a whole Saturday chasing a .005 runout issue on a part I run all the time. Turned out the collet nut had a tiny crack that was barely visible, and it was flexing under load the longer I ran. Swapped it out and got back to my normal tolerances in like 10 minutes. Has anyone else had a dumb mechanical thing eat up way more time than it should have?