"looking things up" To expand on this point, it's not the time it takes to look things up. It's the loops of trying and failing.

I've recently switched from C# to Ruby. In C# I'd consider myself as close to an expert as an ordinary man can get. I never had to look anything up, but more importantly... it was rare that I was confused why something didn't work. In fact most of the time when I saw something not work I knew exactly what I forgot.

In ruby, where i'm less familiar. I'm surprised every now and then. It's not the "go to the internet and search" part that looses time. It's the "let's try this, and see if it works". I might spend an hour on writing 3 lines of code. In C#, I might forget the 3 lines, but I know roughly what they are... and if i had to look it up I can confirm if it's the right 3 lines in minutes.