I also have kind of a bad memory, but thankfully to their relevance to the plot, i have remembered all passwords (actually working ones and those that just appeared in the story) since autumn and never forgot them. Maybe that's because i have wrote a guide for my future self (didn't really used it while playing though). Buut i don't want to write them down here, as it is severe spoilers and i don't want anybody unfamiliar with them to see them. Anyway, good luck with recalling/rediscovering passwords. Maybe you'll write them down, too.