I have printed copies of all my machine manuals. I also save the pdf files on the laptop and a separate hard drive. The printed pages are inserted into the sheet protectors and then into a notebook. Some of the manuals are over 500 + pages. One of my machines had a guide available that cost $125.
The instructions for each specialty foot are printed and in a binder called sewing feet.
I attended a 3 day serger even and have a sample of each activity in the serger notebooks.There is another manual called serger feet. The notebooks are color coded according to my machines. I can easily find what ever I need to look up for reference.