Hm, Chase is almost two and doesn't have a biiig huge full coat, it's nice but not nearly as thick and long others I've seen. I think it might never come with him, but we'll see what happens in the next year.
I had a 7 month old Sheltie here for a week with the thickest coat I've ever seen (would have been fun grooming that), so I guess it varies quite a bit!