Ex techie here. Nothing to add other than when I joined up I was Nav Inst. Then I became Flight Systems (same job, different name) then I became Avionics (same job different name.) Valves were still de rigeur back in my day and transistors were mentioned during trade training as 'the future'.
The most important part of being a techie was to always have an procedure AP in your hand while looking thoughtfully at a broken jet. No one bothered you.
When I became an NCO the most important possession was a clipboard and a pen. Walk 'with purpose' with one of those in your hand and again no one bothered you. I must have walked hundreds of miles 'with purpose.'