Comment by dagw

Make build process 10s faster, 1000 engineers run this 10x a day

Depends where you are starting from. Taking the build from 100 to 90 seconds probably won't make a difference since people will be used to doing something else while waiting for the build to finish in the background. taking it from 10.1 to 0.1 seconds will make a huge difference since you can change your entire development process when builds are 'instant' and you can get constant feedback on any changes you make. Of course the second one is a hell of a lot harder.