One of my clients had me set up their "out-of-the-box" networks two decades back. Long story short: One of the sons came home after retiring from the Army a decade later (as a Major, he worked intel in Europe), he was appalled at his siblings' password 'insecurity' and he and I sat down and ~fixed~ it. Along with a real firewall came alpha-numeric eight and ten character passwords. But we DID write 'em down. That file went into the company safe and a copy came with me to secure. He moved on to other things and the company sold. I've had no contact with them since, but the Major and I remain friends and in contact. [/COLOR]
These days, for all my personal passwords and other sensitive info, I use a program (for Apple only I think) called 1Password. It requires me to remember only one master password to unlock the "vault". There, I can store all my passwords , credit card info, store secure notes, software license keys, bank info, etc. It allows you to create "tags" that you can assign to items that can help quickly find certain types of items very quickly. It also has a really cool security audit section that lets you know when you have weak passwords, duplicate passwords, or passwords that are getting old (6-12 months, 1-3 years, 3+ years old). One of the nicest features is something called "Watchtower" which you can see in the lower left of the second attached image. When you select watch tower, you will see a list of any websites that you have in your logins that have been compromised or had security breaches, thus alerting you that you need to change your password for that site. You can synch your password info across multiple devices by storing your password file (256-AES encrypted) on the iCloud or in Dropbox. That way, all devices always have the most current passwords info when changes are made.
1Password also has an extension for the Safari browser so that, when you go to a web site you can log in by simply clicking the 1Password icon in the browser (assuming you have unlocked the app.). I've used a lot of different password protection programs over the years but this one is definitely the best.
I keep an up-to-date printout of all the passwords in 1Password locked away in a fireproof safe. I periodically go through (at least once a year) and change important passwords, then print a new set and shred the old.