One thing I always recommend prior too installing a major update like OS X Mavericks is to create a USB bootable drive. In case your Macs runs into problems, you can use it to install a fresh version of Mavericks without the need of downloading it again. But one thing is sure, creating one has been a hassle using Disk Utility, and worse, some even recommend using the Terminal. Not anymore.
All you will need to create a bootable USB drive for OS X Mavericks is a USB drive of at least 8GB of storage and download DiskMaker X for your Mac. DiskMaker X will erase everything in the USB drive and copy all files from the OS X Mavericks installer.
To do this, simply insert the USB drive to the Mac, open DiskMaker X and follow the on screen instructions. If you haven't download OS X Mavericks, DiskMaker X will do it. If you have, DiskMaker X will find it on your Mac. Let DiskMaker X create the bootable USB drive and it will let you know when it is done.
If you need to use it, once you power on your Mac, right after the startup chime, press the option (ALT) key and select the USB to install.