iMac Maintenance

The only maintenance you need to do is empty your browser caches now and then,unless you do a lot of video or sound work, defragging isn't necessary. Make sure you also empty the trash, and you could run Applications>Utilities>Activity Monitor to see if anything is hogging abnormal amounts of CPU. Otherwise, nothing needed.

Main thing Mac OS X needs to breathe well, is enough free space on the boot volume. Always keep about 10% or 15% free space and you'll be fine.
Other kind of maintenance you could run, besides Miriam's good advice, would not do any harm anyway but should not make you gain much:
Open Terminal and paste this command:
sudo periodic daily weekly monthly
then hit Return
(your admin password will be required)
then wait for the $ sign to appear again in Terminal, showing tasks are complete. This may take quite some time: dont shut your Mac down otherwise you can use it normally during the "periodic" tasks.

One thing will make your Safari faster:
Remove website icons
(use the "reset Safari" menu).

Of course you can also make sure with a "Verify Disk" run using Disk Utility. If errors found, C-restart from your current Mac OS X install DVD and run Disk Utility from it.

Check out Mac OS X 10.3/10.4: System maintenance .

Should work for OS 10.5x

Regarding the routine maintenance tasks mentioned in Mac OS X 10.3/10.4: System maintenance :

re: 1. CRON tasks automatically run reliably under Leopard; there is no need for this step

re: 2. I agree that cleaning caches every so often will improve responsiveness BUT once a week is much too often -- every few months is often enough for this.

re: 3. Periodically rebuilding the file system directory might speed things up a bit, but the increase is small so don't spend the money on one of these utilities if that is the only reason you are getting one of them.

re: 4. Like with 3 above, defragmenting volumes isn't going to speed things up very much; usually, it won't result in anything noticeable, especially if you follow the suggestion in this thread to keep adequate drive space free.

re: 5. Forced prebinding isn't required or particularly useful, & hasn't been since 10.2 or so. Skip this step.

You have had excellent advice so far, but I just wanted to add my 2 cents:

Repairing permissions is an important part of regular maintenance, and should always be carried out both before and after any software installation or update.

Go to Disk Utility (this is in your Utilities Folder in your Application folder) and click on the icon of your hard disk (not the one with all the numbers).

In First Aid, click on Repair Permissions.

This only takes a minute or two.

Background information here:

http://docs.info.apple.com/article.html?artnum=25751

and here:

http://docs.info.apple.com/article.html?artnum=302672

An article on troubleshooting Permissions can be found here:

http://support.apple.com/kb/HT2963

If you were having any serious problems with your Mac you might as well complete the exercise by repairing your hard disk as well. You cannot do this from the same start-up disk. Reboot from your install disk (holding down the C key). Once it opens, select your language, and then go to Disk Utility from the Utilities menu. Select your hard disk as before and click Repair.

Once that is complete reboot again from your usual start-up disk.

More useful reading here:

Resolve startup issues and perform disk maintenance with Disk Utility and fsck

http://support.apple.com/kb/TS1417?viewlocale=en_US

Repairing permissions is an important part of regular maintenance, and should always be carried out both before and after any software installation or update.

I respectfully disagree with this bit of advice. Repairing permissions is a troubleshooting step, not a maintenance one. Permissions do not go bad by themselves over time; something must mis-set them. Early in the history of the OS, it was not too uncommon for a poorly written installer to inadvertently leave some system files & folders with the wrong permissions, but that hasn't been true since at least the introduction of Tiger, if not long before. Likewise, the Finder in earlier versions of the OS was somewhat buggy regarding showing & setting permissions, which could lead to user error when setting them, but this is not much of an issue with Leopard, at least.

This only takes a minute or two.

I almost spit coffee all over my keyboard when I read this statement! Then I noticed that Klaus was running OS 10.4 Tiger, not Leopard, which explains it. If you run Leopard (like the O.P.) you will notice immediately that a permissions repair is no longer the quickly performed step that it was with earlier OS versions. Allow approximately 10 minutes for it to complete on a fast G5 Mac running Leopard, longer on older & slower hardware.

I do agree with the recommendation to check the health of the disk using Disk Utility from time to time, but note that from 10.4.3 forward you do not have to restart from another disk to do this, thanks to the "live verify" feature that is now a part of Disk Utility. Also remember that Apple recommends using Disk Utility instead of fsck if possible if you are running 10.4 or later.

Repairing permissions is a troubleshooting step, not a maintenance one. Permissions do not go bad by themselves over time; something must mis-set them

Please read the complete sentence you quoted from my post. For example, anything installed from Adobe always requires a permission repair. Repairing permissions before and after an update or install is recommended by Apple.

but note that from 10.4.3 forward you do not have to restart from another disk to do this, thanks to the "live verify" feature that is now a part of Disk Utility.

You cannot repair your hard disk other than from your install disk in the manner described, at least not in Tiger.

In order to repair a disc one must be booted from another disc, one cannot repair the boot disc. Verify, yes - repair - no. This holds true in Leopard as well.

Yes, that is what I said.

Exactly, and I was validating your, as usual, correct statement 😉

Klaus1 wrote:
Please read the complete sentence you quoted from my post.

I did, but I evaluated it in the context of *regular maintenance* that you say should be performed. Installing new software is not a regular event, so even for this consideration there is no need to run that repair more regularly than that requires.

As for Apple's recommendation to repair permissions both before and after an update or install, I cannot find anything more current about it than in (Mac OS X 10.4): Testing and repairing disk permissions, & that only says it "may also be recommended after updating the system or installing new software." AFAIK, this is a reference to the problems with older installers that I previously explained, & is not necessary or even recommended with current installers, Adobe's non-standard installer method included.

From what I can tell, recommending this step for both before & after any update or install, or as regular maintenance, does not come from any official Apple source, & other sources (primarily users with a history of OS X that dates back to the early versions) haven't considered that the advice might be out of date or overkill with the more mature versions now in use.

You cannot repair your hard disk other than from your install disk in the manner described, at least not in Tiger.

True, but as a regular maintenance step, you only need to determine if a repair is necessary. Since it takes some time to reboot from another startup disk, run the repair step, & return to the normal startup disk, I recommend the live verify on the theory that typical users will follow that recommendation more often than with the more time consuming step that requires two restarts.

R C-R, I am not going to respond in any detail to your opinions other than by saying that I am sick and tired of your nitpicking, pedantic interference in my postings, which has been going on for more than a year (I have retained copies of some of your rants), which do not belong in threads in these open forums.

Please prove beyond all doubt that my advice does not work or is in any way detrimental to the technical operation of an Apple Macintosh running OS X, or else keep quiet.

If you must show off and waste everybody's time like this, then please confine yourself to doing so in the Lounge.

I am sorry that you feel that way about my posts, but please note that each of us is entitled to post our opinions. If you believe opinions have no place here, then kindly lead by example & do not post your own.

Also note that my objection to permissions repairs was only to it being recommended as a part of regular maintenance, not that performing that step regularly would somehow be detrimental to the technical operation of a Mac or that it does not have merit as a troubleshooting step.

If you can furnish some reference to a bona fide Apple source stating that permissions repairs should be a part of regular maintenance, I will be happy to revise my opinion about that, but as it stands now I believe users asking specifically about maintenance should know that there is no consensus among users nor supporting documentation from Apple that says it must or should be performed regularly to keep a Mac in good working order.

If one must frequently do that to keep a Mac running smoothly then there is something wrong with the system that needs attention.

More ridiculous semantics.

I need prove nothing to you. You are one that instigated these blatherings and the onus is therefore on you to prove me wrong.

But for the sake of the OP of this thread (the one you threadjacked for your own ego-trip) who may be getting confused, I will refer to the following:

From Disk Utility's Help Pages:

(Also confirmed in KBase Article http://support.apple.com/kb/TS1394?viewlocale=en_US )

If you have trouble opening applications or documents, or if your computer is running slowly, the user permissions for some of your files may be set incorrectly. Permission problems sometimes happen after you update your system or install new software. With Disk Utility, you can repair these problems.

Do not use the computer while installing an update:

Though not required for most updates, you may want to avoid using the computer while installing updates.

From KBase Article HT1452:

When possible, disk permissions should be repaired while started up from a Mac OS X volume (hard disk) that contains updated Mac OS X software, instead of a Mac OS X installation disc. Mac OS X software updates may change permissions on some files to improve security. When this occurs, the version of Disk Utility on the Mac OS X volume is updated to account for the new permissions. Running Disk Utility while started from the Mac OS X volume ensures that the changes made by software updates are preserved.

Lastly:

If repairing permissions is useful in general, why doesn’t Apple recommend it as routine maintenance?

Apple does, quite explicitly:

It’s a good idea to repair disk permissions as a regular maintenance task after upgrading or installing new software.

That’s taken from Mac Help—in both Panther and Tiger—right on your Mac.

Despite what you seem to think, there is nothing personal about this, nor am I disputing anything to further my own ego. I am just trying to include information I think the O.P. might find pertinent about the stated topic of iMac maintenance.

Please note that I have already discussed the potential value of repairing permissions after upgrading or installing new software. However, you wrote that it "should always be carried out _both before_ and after any software installation or update." This seems more than just a matter of semantics. If it had been only that, I would not have posted a response to it in the first place.

I believe that readers should know that for years there has been an ongoing debate about recommending permissions repairs as regular maintenance -- it is not something I instigated just to confuse the O.P. or to "interfere" with the postings of Klaus or anyone else. In fact, the "If repairing permissions is useful in general ..." question is one that appears verbatim in a 2006 MacInTouch Reader Report about permissions in OS X 10.4.6. While I tried to touch on the relevant issues that discussion (among others) raised, I suggest reading that report to appreciate what some respected Mac luminaries have to say about the topic.

It is also worth looking at that help topic reference in context at Mac OS X 10.4 Help: My computer keeps freezing or I see a flashing question mark & to search for anything similar in the Leopard help topics if they are running that OS.

I have been unable to find any similar reference in Leopard's help. If there is one, I would appreciate learning about it.