How to manage the multitude of passwords

Here's the problem: Strong passwords are impossible to remember.

Passwords are a pain. They have to be “strong.” They have to meet the sometimes conflicting requirements of various web services (must contain special characters, cannot contain special characters, case sensitive, more than six characters, etc.). They should be changed periodically and typically can’t be the same or similar to one you’ve used before. Somehow you’re supposed to keep track of them all … in a way that’s secure and not accessible to others.

HELP REMEMBERING PASSWORDS
What is a strong password? It’s a password that can’t be guessed by someone else or easily cracked by hackers. Obviously, your password shouldn’t be your birthday, address or name. It’s recommended that passwords not contain complete words, use upper and lower case letters, contain special characters (unless they’re not allowed) and substitute numbers or symbols for letters. Additionally, the more random the better.
Examples of weak passwords:
• SherylR
• February14
• 123MainSt
Examples of strong passwords:
• R0w1Ing*%
• EyeAM$cPa!
• AY(2Zq7$/
The big question: How can you possibly remember passwords like this? (I can’t even remember why I walked into a room.) Even worse, how can you remember passwords when you have to change them periodically? You can’t write them down on an accessible piece of paper titled “Passwords.” Maybe you can store them in a password-protected file, assuming you can remember the password. You can use online software, but is that really secure?
What is the answer? For now, I’m opting for the password-protected file. I really want to use a simple software service, but I don’t trust that it’s safe. What do you think?
Sheryl Rowling is chief executive of Total Rebalance Expert and principal at Rowling & Associates. She considers herself a nontechie user of technology.