The days of bound engineering lab notebooks (for patent purposes) that would no longer close due to being stuffed full of Polaroid scope photos are long gone, binders do help solve this.
These days keep all your design notes and measurements on a computer. This way you can search for some long-forgotten entry based on a vaguely remembered keyword, and disseminate your notes through email instead of a photocopier. (Patent lawyers might not agree with this philosophy, makes it too easy to fake the dates.)
The main thing is to write everything down. You never know what you may need at some future time.
I use a lot of 3-ring binders, so many it's hard to store them all. I don't use them for everything. For day-to-day notes and planning, I far prefer college-ruled composition books with "granite" covers. They're a nice size, light, and easy to take on public transportation. I carry them everywhere.
I'm also a strong believer in documentation -- the earlier the better. When I'm working on something new and don't know what I'm doing yet, the notebook is excellent. However, once I can start to describe it I find that writing it up using a document editor is a great way to get the ideas filled in, and it becomes the first draft of the eventual documentation. The hard copy goes in binders.
I find it very hard to proof-read on a screen. I always find errors after printing out on paper.
IMO everyone should print hard copy listings of their software and technical references. If doing so creates so much paper that you can't manage, then your design approach clearly needs to be reconsidered.
The challenge of documentation is that it is usually intended for retrieval in the future. This means that the effort of documentation has little immediate reward and the future retrieval depends upon maintaining access integrity through time. Three ring binders are bulky and hard to search but admirable in their accessible user interface through time, changing computer software, and operating system. Computer files must be created in a format for which future access is assured and the files must be rolled ahead to each new generation of the storage system. They must also be preserved in a way that is obvious to others. Most computers are reused or retired when their owners retire or pass away. Few files are effectively captured and mined for the corporate benefit. Lab books are visible which at least forces somebody to consciously decide whether to preserve or discard them. Someday, our ability to create data will be matched by our ability to mine it. In the meantime, most recollections of previous solutions depend upon the memory of the inventor; the documentation merely fills in the fine details. The next generation has little hope of mining the digital records of their predecessors.
I can't pretend that I have any good methods for capturing and maintaining documentation, but I do love the file management system an engineering friend of mine has: I was leaning over his shoulder recently while he was working on his laptop and I noticed he had three folders on his desktop: crap, more crap, and even more crap. He told me that was where he stored the "important" content!
@DrQuine - The challenge of documentation is that it is usually intended for retrieval in the future.
What I have found using the smaller one inch binders is that this size works for keeping the quick reference stuff. The few pages of the data sheet one needs to access quickly like the pinouts and footprints. I also keep the schematic, and BOM in these thin binders. I like to think of these as aking to the "pocket program guide." for easy quick reference.
Size does matter here as I like to reference some of these as a bedside reader. The photograph was taken literately on my bed. This size is also useful in the bathroom. Granted one can take the laptop, or phone into the loo (head or necessary) Given that most of these now have Orwellian cameras on them, I am not sure I want to do that. Or for this natural engineering and salty sailor talk topic to continue.
@Karen - My folders are quarantine, sandbox and guff. Then there is the evenMoreGuff folder. Disks and now thumb drives that I sneaker net with are called Noah, and ark. These then go into quarantine.
I like to document my work with the help of a simple technique: locality of reference. This means that I keep at hand those things that have equal importance to a project, even if I don't use them. Not only that, I label each section using the alphabets A,B,C etc, and write a summary of contents on top of every label. If I need a document on Software Post Processing that has been labelled in "T" and if the topics Software String Management in "Z" and Software Code Debugging Models in "R" are equally important to the project (even if they are not needed), I group the labels T,Z and R together.
@Spike_johan: Interestingly, this is what most trainee engineers suffer from in their first couple of years. "If you didn't write it down, you'll forget it" and "If you didn't write it down, you didn't do it". It is through hardship do they understand the importance of physical documentation. Going tech-savvy is good, but in order to build a technology, paper documentation is required.