Once you are at your limit of nine, you can remove subject areas you have already done and replace them with others. This works for me because I only study one subject at a time. If you are studying 10 or more at one time, I can see where this is an issue for you. But if you are studying fewer at one time, you can remove ones you have already mastered or otherwise completed.

I  would like to second the original posters comment x10.

As someone who has a lot of varied technically based interests - I think it would most excellent if we could up the limit to the number of tracked courses to something a bit more "current day".

1) I want to always be able to come back and see what course I've taken AND also see if there is additional content added for them.

2) Some, like myself prefer to bounce around and pick and choose bits from various courses rather than linearly going through course after course. I find this works better because our brains are associative memories - the more connections there are to some fact or data - the easier it is to recall said fact or data. Across different scientific and technical subjects we tend to see the same "things" presented/manifested in different manners - this actually helps understanding and retention of knowledge IMO.

Thanks for reading.