Things you only do ONCE!

[RobotDoktor]

Definitely don't drill anything metal, sharp, or both while holding it with your hand. Fortunately the scar is pretty much gone now.

Other things to avoid:

• Cutting small parts on the chopsaw (it will go flying)

• Leaving the chuck key in a drill press/lathe/mill

• Holding resistors while soldering them

• Stalling AM9015 motors (burned out the motor and melted the brand new Anderson connectors)

• Send poorly dimensioned drawings for machining

I should point out that CAD autosave is not a thing because of the time it takes to save assemblies of hundreds of parts.