Thanks for the great series of articles. I started using the extended properties when I got a tool that would create database documentation based on those properties.
I found that I had many columns with the same name and were really the same item in various tables. For example, many tables had the "AccountID" column, and all were copies of the same thing (primary key in the Account table, foreign key in all other tables). When writing the statement that creates the sp_addextendedproperty, I found it helpful to try to locate another field with the same name and use that as the default value. That allowed me to save a lot of retyping. Of course, I had to review each generated statement for accuracy and make changes as necessary, but it was better than having to look up what I created for the previous tables and retype or copy/paste every time. For my defaults, I used the most-frequently-used description for columns with the same name.
Again, thanks for the thorough explanation and the helpful examples.