There are a number of things you can do to keep your Mac running quickly and smoothly and also prevent loss of data. It is suggested that you make a schedule of maintenance that you follow. How many different applications you use, how often you use them and the importance of the information generated will dictate how often you need to do these chores.
 
For those who use quite a number of applications and/or use their machine over 20 hours a week that a monthly run of Disk First Aid would be sufficient. For those who (or whose children) run high memory games or try many applications downloaded from the Internet, it would be advisable to do this weekly. If all you do is work with a word processor and use your email then less frequently will suffice. 
 
Disk First Aid
 
Disk First Aid (DFA) is your first line of defense when things are not well and also as preventive maintenance. You will find DFA in the Utilities folder on your hard drive. You should restart with all extensions turned off (restart holding the shift key down until you see the opening splash screen) or start from a disk other than the one you want to check (a bootable removable disk like the Mac OS system disk or secondary volume). An older version of DFA can not repair the startup disk or disk it was launched from.
 
Select the drive you would like to check and click on the “Verify” button. DFA will do a series of checks of the selected drive.
 
If DFA finds any problems you will be alerted. Click on the “Repair” button and DFA will attempt to repair the problem. Most often it is capable of repairing any errors it finds.
Shut down your Mac properly. Using the shut down command from the Menu or the by using power key, choosing Shut Down from the dialog box which appears. It is a good idea to shut down your Mac at night so that each morning you start with a fresh system minimizing the possibility of continuing with yesterday's possible conflicts.
 
 
Software Update
 
Keeping your Software up to date is a great way to avoid running into any conflicts with your system.  Simply got to System Preferences, click on the Software Update Icon, click the Check Now Button and it will search the web for new updates for your Mac.
 
You can set your system to do this automatically for your either Daily Weekly or Monthly.  You can also have it set to install important updates for you automatically.