I still have a few hundred Casebeer books which made their way to a midwestern show more than a decade ago. Some had the famous (or infamous) Casebeer color touches and some didn't. If it wasn't obnoxiously obvious, some of those books made my core boxes with a little note in the bag denoting "From the Collection of Lance Casebeer." If I already had an equal or superior copy, I just kept the Casebeer books with their original post-it notations in their original bags as part of a quirky chapter in paperback collecting history.
Regarding run collecting, I still fill holes when I can do it on the cheap, which means rarely buying on eBay because the postage kills you - that's what really adds up over the years. And frankly, I still like too many publishers to get caught in that cumulative postal trap. Take Pocket, for instance: I'm that guy who likes all those vegetable gardening and Vogue dressmaking editions. Again, I think them quirky and worth preservation. I'm more of a generalist than a run collector - albeit a generalist who likes way too much stuff, such that it starts to look like I'm a completist.