The one piece of custom code I added to the blogCFC engine that I wanted back was the ability to customize the keywords on an individual entry. I wrote that code 3 years ago and certainly don't recall what I did. However, it was easy to add back in.
I wrote a blog post about it! It was quite surreal to read my own blog post on how to update blogCFC to do what I wanted. But, it took 5 mins and boom, it was back in place!