If you have an Apple computer and are not using Time Machine, you are missing out. Time Machine is part of the Mac operating system (OS). Each day I come into my office, I just plug in my external hard drive. It automatically reads it and records any files that have changed. It will use up all the available memory on the hard drive and then delete the various versions so that it maintains a monthly, weekly, daily, and hourly backup. While plugged in, it will automatically backup each hour. The one caution as with however you back up, don’t carry the external hard drive with the laptop because if you bag gets stolen or lost, they both go.
Although this is a fantastic way to backup your machine, I was extremely impressed last week when I changed to a new computer. Again, a program within the Mac OS called Migration Assistant helps you setup a new computer. I simply selected setup machine with data from my Time Machine external hard drive. I started it up and let it run while I did some other things. In about 2 hours, the laptop was completely setup including my system preferences, account logins, printer and wireless settings, and even the desktop background. I just made a couple clicks and it was done. Very impressive.
My advice...use Time Machine if you have an Apple.