Rule Two: Keep your eyes open for free paper.
Rule Three: Different kinds of printing, type, cuts, and ink require or at least work better with different kinds of paper. See rules One and Two above.
Rule Four: The fact that the paper is free will not improve your printing, but it doesn't hurt.
As you can see from the photos, I've been following the above rules. In fact, I had to recently build the upper shelves on the left of the first photo to make room for more. The large sheets of paper (and metal shelves) to the lower left in the first photo came from the garage print shop where I got my first press at the time I was just starting out two years ago. More came from various sources usually in conjunction with picking up something else where it was thrown in to get rid of it. There is everything from Kromcote to mimeograph; ledger to bond; book to chipboard; diecut cards to tag. I even came across stacks of pre-printed colored-border award certificates in different sizes. Did I mention some boxes of envelopes too?
I've experimented with a lot of it and can recommend that it is good to have different kinds of paper around. E.g. Cuts that don't print well on one kind will print perfectly on another. I suppose this seems like a no-brainer but I've noticed that there are many printers who seem to use one or two kinds of paper exclusively, usually the ubiquitous Lettra.
The issue of free comes up for a number of reasons. First, I am poor and by rights perhaps should not have printing as a hobby at all when one looks at the prices a lot of printing equipment, especially for letterpress, seems to go for. But where there's a will, there's a way and usually a lot of generous people to help. At least that's been my experience and I'm grateful to all of them. Second, there's a lot of good quality old paper laying around and it seems like a good idea to recycle it this way instead of having it go to a recycling center where it can be made into a lot of modern poor quality paper. Third, it's just plain fun.
Say, anyone in the central New Jersey area have any paper to get rid of...?