I do not know how long I have been using a simulator. I have used a computer since the mid-1980s, so I must have used a simulator since the mid-1990s. I belong to the slide rule generation that used to draw their circuits on paper with a pencil and do their design using a slide rule. I recollect that some engineering departments had courses that taught slide rule use. It was a big step forward for me to use a calculator, and it was a revolution to use a computer to draw circuits and PCB layouts on the screen.