That means carrying around a bulky external hard drive with cables is not always ideal. And since most Mac owners use a MacBook of some kind nowadays, portability is a valuable thing. A clean installation of the operating system can help pinpoint problems and will come to the rescue in a bind.
One of the maintenance tools every Mac user should have available in case of emergency is a bootable copy of Mac OS X on a removable device.
All you need to do is carry around a single USB flash drive to be ready for situations the require you to diagnose, repair, or experiment with Mac OS X. Although Macs are reliable machines, they are not exempt from hiccups.
