I guess that can be true for some people. I didn't make sigs for like, i don't know, 4 months, and it wasn't that hard to get back into. I think the key is coming up with something new, whether it be brushes or effects, and run with that. From that you can evolve your work into more rounded stuff. And maybe after a while, you'll start to pick up the stuff you forgot. At least thats how it was for me. But whatever it is, I just find working with photoshop and sig making and stuff really enjoyable.