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Well I have to write everything down. I'd get into a right mess if I didn't. Nobody is going to see my little black book of passwords unless they break in to my house. Not likely where we live thankfully. I don't think I'm an idiot and I'm sure you're not either Swim.
I use a Password Manager called Keepass and the encrypted file it creates is kept in OneDrive so it pops up on all my devices. Now I am comfortable with it I use it to create my passwords too. It generates passwords like:
4xCGMeVg
Which I don't need to remember because it does it for me
As you point out the only flaw is remembering the password to get into Keepass but that combination is a series of numbers and letters I am very familiar with and the only one I have to remember.