Well, you mentioned stamps without "worth"... I myself got rid of ALL my BRD commemmorative and special issues, I only kept the "mass" stamps.
Why? Because I like them better and I neither have the time to sort nor the space to keep all these stamps in stockbooks.
Now I "reduced" my interest BRD-wise to these mass stamps in all their varieties. That's a very cheap area, as well as a very interesting one because you can dive deeper into all the varieties, plate errors, and so on. I think this is more interesting than just trying to gather all the "main numbers". There's nearly no "discovering" in collecting main numbers only, checking them in your catalogue.
I do this as well, for example with my DDR collection, where I collect main numbers only. But nothing beats digging through piles and piles of cheap stamps, "exploring"
