When you own a lot of gadgets, software, and belong to several forums, how do you keep track of need to know information?   You could build a spreadsheet with the pertinent information, but what if your computer fails and you haven’t backed it up?  I used to keep all my information about my purchases in a journal, but after awhile it became so disorganized.  Now I use a paper address book.  Now I can enter information alphabetically.   The information I keep includes the name of the device, software, website, and serial numbers, tech support phone numbers, user ID, passwords, etc.  Basically everything and anything I think I may need. I find this has been not only a quick reference, but also serves as a historical catalog of my purchases.  I also keep information associated with extended warranty purchases. I often go back and write notes when I have to call a vendor, or if I decide that the product sucks.  It also helps when I reformat my computers and need all my registration information to reinstall applications.  Sometimes I keep non tech info too, like my son’s wall locker’s combination, and for my youngest, his lunch PIN.