It's not just all the new stuff that's emerged in the last 30 years. I feel like I didn't really understand a lot of the fundamentals like I thought I did back in my 20s and that there were some major holes in my education that only became apparent after some years of experience in the field. Often you don't know what you don't know. I now know there's a lot I didn't (and don't) know and I think that's a valuable thing that mostly only comes with experience.