If you use your computer for just playing games, browsing the Internet and have an online email, the only files you may want to backup are your bookmarks/favorites and your saved games. However if you also have some media files (like mp3s, pictures, movies, etc.) and especially if you use your computer for work, you need to make regular backups.
It’s up to you to decide which backup media to use – CDs, DVDs or external hard disk, and how often you will backup – daily, weekly or as soon as you create a new file. You can even use a dedicated backup software, however most of these programs are targeted at business and corporate users and can be quite complicated. For a home or a small business: the simpler the backup process is – the better it works and the chance of failed backup or error is smaller. Best is to just copy your documents and arrange them in folders by date.
There are some advantages and disadvantages to the different types of backup media:
CDs and DVDs are very cheap but have limited capacity. They have good lifespan, usually 5 to 10 years, and are very sturdy, but you will need a good large case to store them and some kind of filing system, so you can easily find that document you typed two years ago when you need it. Also some brands of CDs and DVDs last a lot less than others and can go “bad” in just a couple of years. For best results and longevity use either premium quality, Verbatim or Taiyo Yuden. Also I would advise against using re-writable disks. There’s no point in buying a more expensive CD that has higher chance of failure, just with the hope that you will erase it and use it again. With both CDs and DVDs costing about $0.30 – $0.40 each, why would you want to erase and reuse them.
External hard disks are quite large, currently the “usual” size is 250GB or 320GB and that will go to 500GB soon. You can store a lot of files on one of these and quickly and easily find anything you need. However like all electronic devices they break if you drop them and although portable, it’s not a very good idea to carry them with you. Furthermore all external hard disks suffer from the same failures like the internal ones and need to be scanned for errors regularly.
Flash memory in any form (USB flash drives or memory cards – SD, MMC, Memory Stick, etc.) are not good backup media. They are not only small in capacity, but also have a finite number of writes and will fail after it’s reached.
Another backup option for a smaller number of small files like text documents, spreadsheets, a few important pictures, etc. is to make an online email account at gmail, yahoo, hotmail, etc. and email them to yourself. That way you will be able to access them from any Internet connected computer and also you can keep them for years.
And finally: you should never email or backup sensitive information without encrypting it first.