By now, regular backups are a normal part of your routine: your backup software automatically updates your archives every day and your duplicates once a week, and you diligently rotate backup media offsiteright? Even so, I recommend adding one final element to your backup regimen: archival DVDs.
If you've followed my advice, you already have archives of all your important filesgoing back several months or moreon each of two or more hard drives. You also have one or more complete, bootable copies of your main hard disk as it existed at some recent time. This is all good, but some problems remain:

• Hard drives don't last forever. Sooner or laterin a year, or five or ten yearsyou'll no longer be able to access the data on your drives.
• Because archives constantly get bigger, the archive can eventually outgrow the drive you store it on.
• As your main hard disk fills up, you may want to delete files periodically to save space and yet be able to retrieve those old files if you later need them.

I'm aware of several schools of thought regarding archival backups, so bear in mind that this is just one person's take on the process. In a nutshell, I recommend this: once a year, make a copy of all your backups (both archive and duplicate) onto a stack of DVDs, store them in a safe place, and then recycle the hard disk you use for archives by erasing it and starting over with a new, full backup. By doing this, you hedge your bets against hard drive failure, free up valuable space for archives, and give yourself a safety net in case you want to prune files on your primary hard disk.

Note
I hasten to point out that DVDs don't last forever either, but if you store them carefully in a dark, cool, dry place, they should be readable for ten years. By the time you approach that point, if you still want to keep the data, you should migrate the contents of your discs onto new media.

To archive your data, obtain a big stack of recordable DVDs and follow these steps:

Now that you have a safe copy of all your data, you can consider deleting files to make extra space on your main hard drive, as I describe in the following section.

Remove Unneeded Files

Just as your home probably needs a good spring cleaning once a year, your computer can use a digital tidying-up now and then. So take this opportunity to get rid of applications you don't use, outdated files you'll never look at again, and any other crud that has gathered in the dark corners of your hard disk.
The process is the same one I described near the beginning of this article. Flip back to Clean Out Accumulated Cruft for complete instructions, and repeat that procedure now.

Change Your Passwords

Passwords are a fact of life in the wired 21st century. You probably have dozens or even hundreds of passwords, such as these:

• Your Mac OS X administrator password
• Passwords for .Mac and any other email accounts you may have
• Passwords for Web sites and other online services
• A password for your AirPort base station, and perhaps another one for your wireless network
• Passwords that protect encrypted files, folders, or volumes (such as your backups)

It's easy to become lazychoosing short, easy-to-type (and easy-to-remember) passwords and reusing the same password in multiple places. The Mac OS X keychain enables you to store most of your passwords in one place and access them easily, but it can also contribute to password laziness by keeping you from noticing how often your passwords are required.
If you're the only person who uses your computer, and if you don't access sensitive information online (such as bank accounts or proprietary corporate data), you can probably get away with relatively few passwords that remain the same indefinitely. Otherwise, I strongly recommend changing your passwordsat least, those that protect the most sensitive informationonce a year (or more often). That way, if someone were to guess one of your passwords, it would be useful for only a limited period of time.

Look for Passwords to Change

Each Web site, application, or device has its own procedure for changing passwords, and I can't begin to cover them all here. I will, however, mention a few common places to look:

• To change your Mac OS X user account password, go to the Accounts pane of System Preferences. Select your user name in the list on the left and click the Change Password button in the Password view.
• To change your .Mac password, go to www.mac.com and click the Log In link on the right side of the blue .Mac tab, which runs across the top of the window just under the row of tabs. Enter your member name and password. Then click your member name on the .Mac tab (logging in again if asked to do so) to display the Account Settings page, click Password Settings, and follow the instructions.
• To change the password used by your AirPort base station or your wireless network, open AirPort Admin Utility (in /Applications/Utilities). Select your base station and click Configure. Then, in the AirPort view, to change the password of the base station itself, click Change Password. To change the password of your wireless network, click Change Wireless Security.

In addition, I recommend opening Keychain Access (which is also in /Applications/Utilities) and looking through the passwords stored there. That will give you an important reminder of many of the Web sites and applications for which you've already established passwords.

Choose a Good Password

You've undoubtedly heard this sermon before, so I won't beat you over the head with it, but let me briefly reiterate the qualities of a good password:

• Longer is better: A 16-character password is much more secure than a 6-character password, and even longer is better still.
• No common words: Don't use a word (or words) from the dictionary as your password; a hacker can break it easily. Also avoid words and numbers people might guess: your favorite color, date of birth, pet's name, and so on.
• Mix letters, case, and numerals: Every password should include at least one uppercase letter, at least one lowercase letter, and at least one numeral.

Luckily, Tiger includes a tool to help you create passwords that meet these requirements: Password Assistant. Whenever you create a new password (for instance, in the Keychain Access utility or in the Accounts pane of System Preferences), a button appears next to the New Password field. Click this button to display Password Assistant
To use Password Assistant, follow these steps:

6. Things You Might Never Need to Do
Careful readers may have noticed that I omitted two common tasks from my recommendations of periodic maintenance procedures: repairing permissions and defragmenting your hard disk. Read this article to discover why you might never need to do these thingsor whether you're one of the few people who should.

Repair Permissions

If you visit Mac discussion forums, blogs, and news sites, you've probably seen repeated recommendations to use Disk Utility's Repair Permissions feature. Some people recommend repairing permissions on a daily basis, or before and after every software installation, or as a first troubleshooting step when any sort of problem arises. Anecdotes abound about the seemingly magical curative (or prophylactic) properties of this feature, so it has achieved a sort of mythical statusin much the same way rebuilding the desktop file was a standard cure-all under Mac OS 9.
At the risk of being labeled a heretic, I'd like to suggest that in most cases repairing permissions is nothing more than a placebo. True, the procedure can solve certain problems and rarely does any harm, but as a routine maintenance task, I consider it a waste of time. To explain why, I should provide a bit of background.
In Mac OS X, each file contains information specifying which users (or parts of the system) can read it, modify it, or execute it. This information is collectively known as permissions. If a file has incorrect permissions, it can cause applications to misbehave in various ways, such as crashing or failing to launch.
Ordinarily, installers set the correct permissions for the files they install, and the permissions stay that way permanently. However, a poorly written installer can mess up permissionseven for files it did not installand if you use Unix commands such as chown and chmod, you can accidentally set files' permissions incorrectly. These sorts of problems occur infrequently, but they do occur.
The Repair Permissions feature looks for software installed using Apple's installer, which leaves behind files called receipts that list the locations and initial permissions of all the files in a given package. Repair Permissions compares the current permissions to those listed in the receipts and, if it finds any differences, changes the files back. The command ignores software installed in other ways (using a different installer or drag-and-drop installation, for instance) and knows nothing about legitimate permission changes you may have made deliberately.
Although I said earlier that some kinds of disk problems can occur without any provocation (see the sidebar Why Do Disk Errors Occur?), permissions don't go out of whack all by themselves; you (or software you install) must do something to change them. And not all changes are bad; in many cases, a file's permissions can be different from what they were originally without causing any problems. So repairing permissions makes little sense as a regular activity.

Note
I should mention that Apple suggests repairing disk permissions after installing new software. I suspect that their reason for doing so is to head off tech support calls about problems resulting from the use of a few poorly written third-party installers.

I do, however, recommend repairing permissions as a troubleshooting step if (especially right after installing new software) you find that an application no longer launches, or produces inexplicable error messages. To repair permissions, follow these steps:

Disk Utility resets the permissions of files installed using Apple's installer.

Tip
For much more detail about working with permissions, I recommend reading Brian Tanaka's Take Control of Permissions in Mac OS X (www.takecontrolbooks.com/permissions-macosx.html).