Having spent a fair bit of time working in large projects in dynamic languages I think compile times are completely overrated as an issue. Much more important is build times. That is compile, test, package loops. I hardly ever compile in isolation. I am usually running tests, doing code generation, building artifacts as well as compiling. As soon as this is true, compilation times tend to be dwarfed by the rest of the process. Thus my point about compile times being low on my priority list (though I won't defend them).

For instance, lots of people mention Go compile times during discussions such as this and I find that argument non-compelling for the simple reason that on small projects the difference is imperceptible and on large projects the other factors I mention dwarf compile times in either case.

I will say thanks for the concrete time period definition though. 5-10 second turn around seems like a trivial time to argue about to me. If I have to look up from my editor for 1 second it might as well be 30. Anything more than 30 is context switch time. I haven't had to deal with incremental build/test loops longer than 30 seconds in a long time and Scala certainly doesn't require them. Again, I'm perfectly willing to concede this could be a generational difference as I've worked on projects that had compile times measured in hours and (automated) test cycles measured in days.