Posted By:
robert aHi Bob,
It seems like I'm always on the verge of breaking up an uncompleted set, but I actually end up doing the opposite.
I trade away all of my harder types for cards that will fit into a set. I too usually end up regretting it, but I enjoy the hunt of completing a set.
Although, I have done it before. It's funny you mention E97. I tried that one. 
Robert