Ah, Chainsaw, an excellent point. I don't think I planned any of it. Initially, I split all the books up to make it easier for me to update things without everyone having to download the whole thing every time but with broadband nearly universal I'm putting them all back into a single book!
I think it might also be worth mentioning that most of the fun I have with Icar is the actual act of creation. Even when I get Icar Version 4 finished, I'll still find something to tinker with.
Are you the same?