I worked in the microscopy branch of Thermo Fisher Scientific, where I serviced small dual beam microscopes (SEM and FIB) at vendor sites mainly around Austin, TX but occasionally other places in the US. I also learned about the theory of how these microscopes work, which encompasses many different aspects of engineering. Every day I was challenged with a new problem to diagnose and fix, and every day I learned why and how the designers designed the tool in the way that they did. I worked on both older microscopes and newer ones, and I could see the progression between generations and steps the designers took from machine to machine. The senior engineers that I worked with passed down their tricks and explanations about the machines from a service side perspective, including poor design decisions on older machines that the service engineers had to deal with.