Question: how long does it take to come up with an idea

Colin Keogh answered on 10 Nov 2014:

Coming up with ideas can be very fast or very slow. Some ideas hit you suddenly, which i then have to get down on party very quickly so i dont forget. This is very rare though, so doesnt happen often.

Normally ideas come from working on similar projects for a long time, over which your ideas slowly grow to make the process/invention etc work better. This is the normal way engineers get ideas. They learn about a problem and them think up ways to make it better.