Q: What software is recommended for the maintenance of mac?

OS X has pretty much everything you need under the hood.  I recommend periodically running Disk Utility (in your Applications -> Utilities folder) and repairing disk permissions to check for and clean up any minor errors.  You can use the repair disk option to scan and repair any errors on external drives. 

To repair the disk on your boot drive (under I believe OSX  and above), reboot the machine and hold down the Option key while doing so.  You'll then be shown options to boot to different drives, choose your Recovery Partition and then once that loads run Disk Utility from there and you can repair your main boot drive.

There are a variety of apps out there in the utilities category, I don't know that I'd call any of them "must haves" - though ProSoft's Drive Genius 3 is generally highly recommended.  It's a bit spendy, but if you've got a lot invested in storage options you'll get a lot out of the program.

Maintenance is done automatically at scheduled intervals.

http://support.apple.com/kb/ht2319

How to maintain a Mac

1. Make redundant backups, keeping at least one off site at all times. One backup is not enough. Don’t back up your backups; all should be made directly from the original data. Don’t rely completely on any single backup method, such as Time Machine. If you get an indication that a backup has failed, don't ignore it.

2. Keep your software up to date. In the App Store or Software Update preference pane (depending on the OS version), you can configure automatic notifications of updates to OS X and other Mac App Store products. Some third-party applications from other sources have a similar feature, if you don’t mind letting them phone home. Otherwise you have to check yourself on a regular basis.

Keeping up to date is especially important for complex software that modifies the operating system, such as device drivers. Before installing any Apple update, you must check that all such modifications that you use are compatible. Incompatibility with third-party software is by far the most common cause of trouble with system updates.

3. Don't install crapware, such as “themes,” "haxies," “add-ons,” “toolbars,” “enhancers," “optimizers,” “accelerators,” "boosters," “extenders,” “cleaners,” "doctors," "tune-ups," “defragmenters,” “firewalls,” "barriers," “guardians,” “defenders,” “protectors,” most “plugins,” commercial "virus scanners,” "disk tools," or "utilities." With very few exceptions, such stuff is useless or worse than useless. Above all, avoid any software that purports to change the look and feel of the user interface.

The more heavily promoted the product, the more likely it is to be garbage. The most extreme example is the “MacKeeper” scam.

As a rule, the only software you should install is that which directly enables you to do the things you use a computer for, and doesn't change the way other software works.

Safari extensions, and perhaps the equivalent for other web browsers, are a partial exception to the above rule. Most are safe, and they're easy to get rid of if they don't work. Some may cause the browser to crash or otherwise malfunction.  Some are malicious. Use with caution, and install only well-known extensions from relatively trustworthy sources, such as the Safari Extensions Gallery.

Never install any third-party software unless you know how to uninstall it. Otherwise you may create problems that are very hard to solve.

4. Beware of malware. Malware is malicious software that circulates on the Internet. This kind of attack on OS X used to be so rare that it was hardly a concern, but it's now increasingly common, and increasingly dangerous.

There is some built-in protection against downloading malware, but you can’t rely on it — the attackers are always at least one day ahead of the defense. You can’t rely on third-party protection either. What you can rely on is common-sense awareness — not paranoia, which only makes you more vulnerable.

Never install software from an untrustworthy or unknown source. If in doubt, do some research. Any website that prompts you to install a “codec” or “plugin” that comes from the same site, or an unknown site, is untrustworthy. Software with a corporate brand, such as Adobe Flash Player, must come directly from the developer's website. No intermediary is acceptable, and don’t trust links unless you know how to parse them. Any file that is automatically downloaded from the web, without your having requested it, should go straight into the Trash. A web page that tells you that your computer has a “virus,” or that anything else is wrong with it, is a scam.

In OS X 10.7.5 or later, downloaded applications and Installer packages that have not been digitally signed by a developer registered with Apple are blocked from loading by default. The block can be overridden, but think carefully before you do so.

Because of recurring security issues in Java, it’s best to disable it in your web browsers, if it’s installed. Few websites have Java content nowadays, so you won’t be missing much. This action is mandatory if you’re running any version of OS X older than 10.6.8 with the latest Java update. Note: Java has nothing to do with JavaScript, despite the similar names. Don't install Java unless you're sure you need it. Most people don't.

5. Don't fill up your boot volume. A common mistake is adding more and more large files to your home folder until you start to get warnings that you're out of space, which may be followed in short order by a boot failure. This is more prone to happen on the newer Macs that come with an internal SSD instead of the traditional hard drive. The drive can be very nearly full before you become aware of the problem.

While it's not true that you should or must keep any particular percentage of space free, you should monitor your storage use and make sure you're not in immediate danger of using it up. According to Apple documentation, you need at least 9 GB of free space on the startup volume for normal operation.

If storage space is running low, use a tool such as OmniDiskSweeper to explore the volume and find out what's taking up the most space. Move seldom-used large files to secondary storage.

6. Relax, don’t do it. Besides the above, no routine maintenance is necessary or beneficial for the vast majority of users; specifically not “cleaning caches,” “zapping the PRAM,” "resetting the SMC," “rebuilding the directory,” "defragmenting the drive," “running periodic scripts,” “dumping logs,” "deleting temp files," “scanning for viruses,” "purging memory," "checking for bad blocks," "testing the hardware," or “repairing permissions.” Such measures are either completely pointless or are useful only for solving problems, not for prevention.

Let go of the Windows mentality that every computer needs regular downtime maintenance such as "defragging" and "registry cleaning." Those concepts do not apply to the Mac platform. The machine should not be a focus of your attention. You shouldn't have to think about it at all. It should be a transparent, almost unnoticeable tool by means of which you communicate, work, and play. If you want a computer that depends on you to keep going, use a PC.

The very height of futility is running an expensive third-party application called “Disk Warrior” when nothing is wrong, or even when something is wrong and you have backups, which you must have. Disk Warrior is a data-salvage tool, not a maintenance tool, and you will never need it if your backups are adequate. Don’t waste money on it or anything like it.

Everything I needed know. Answers the questions I wanted to ask.

backups, so perhaps use $$ for something besides TimeMachine, and more than one backup drive and method. a working bootable clone of your system is very valuable. take away worry of lost files and photos.

This is one of the most helpful comments/responses noted on the support groups. I would like to compliment you on the thoroughness and detail of of your reply. I personally find that the multiple individuals who take the time to assist us, should be commended.

A big THANK-YOU!

If you are using an SSD for your system or your data, I think there are things to know and be aware of that are unique to SSDs.

One reason for the "10%" free space was that it was observed that it does get slower to find free space to write or update a file, it traditionally increased the time to seek for files. And, free space can get highly fragmented. Also the ability of HFS+ to manage large drive directories and write changes to the directory.

Video editing and other uses, that were more common on the Mac Pro and earlier may require disk I/O to not drop below a given level.

Optimizing your storage for specific needs and purposes for say CS6 will take into account other needs that do need to be addressed. The boot drive will be used for cache purposes and will be a factor especially when using SSDs that do not have 100GB or more of free space.

I tend to think Mac Pro users are not just doing office and web browsing and need to know their systems better.