I would think that it depends on how structured your code needs to be. For example, I'm working on a soon-to-be open source project which makes heavy use of pr

I would think that it depends on how structured your code needs to be. For example, I'm working on a soon-to-be open source project which makes heavy use of prototypical inheritance, so I use it a lot. That being said, for one-off projects that do not require a lot of extensibility, you might not use it at all.