some criticism: what if you are actually tech informed and know what type of password to make like foe example “a master password consisting of memobrale letters” and then adding something at the end relating to that app like “masterpass01mine” for minecraft
Your 16 character password works just fine! The only idea of calling something a passphrase is purely for the fact that it will be longer due to it being a phrase and not one word, and it will also be able to be remembered instead of just random letters and numbers. So if you have a long 16 character word that you remember consistently, then you're already killing the game!
So you don't need symbols, upper case/lower case, etc.? Just type in a sentence like "ilovesecuritysomuch" and because it's 19 letters long, it's a good password?
Length is the determining factor. You can still include symbols, upper/lower case etc. It is great to include spaces in the sentence as well. This is what security experts have concluded and mathematically proven.