Before you even think of buying a backup program you really should ask yourself a critical question:
"If my PC was stolen tomorrow what data would I really miss?"
Now some folks, a very few I suspect, would be able to answer "I wouldn't really miss anything."
If that's your honest opinion then you don't need a backup program. You might as well exit this site now and use your time more productively.
However most people would give answers like:
Those who use a PC to help run a business might additionally answer:
Backup is about protecting this valuable data so that you can get it back quickly and without errors.
And you can lose it in many different ways. Theft, fire, earthquake, storm damage are certainly risks. But probably the most common way is computer failure - hard disk failure in particular.
If your hard disk crashes, there's a good chance that all the data on the disk has been lost forever. If you haven't got a copy, it's gone. Simple as that.
If you can't bear such a loss, you'd better get serious about backing up. Unfortunately, hard disk crashes happen all too regularly. I've had four in ten years!
But there's worse to come. Apart from losing you data you may also lose something equally important; the use of your computer.
This is not a trivial issue. For some folk, the ability to utilize their computer may be just as important as the data on it. Take for example, a support analyst who needs access to email or an insurance agent who needs to use a spreadsheet to generate quotes.
If these people suffer a hard disk crash or other computer loss they not only want get their data back quickly they also want to get back the use of their PC.