I think there is a relatively simple rule of thumb: If you can reliably memorize the password with moderate effort, it is very likely not safe. The approaches described in the linked article are clever but they do by far not exhaust the possibilities. One big issue is the following: When you try to come up with random words to compose a password, the words that you'll choose are going to be very very non-random. Example: Tell a person to name a random musical instrument. Most people will say violin or piano. Other instruments will rarely be mentioned. Likewise with tools, most people will say hammer or screwdriver. This has something to do with how words are represented in our mental lexicon. There is a lot of research on that that you could easily leverage in software for cracking passwords, at least the type of password that's using supposedly random words.