As I explained in the previous lesson on encrypting your wallet, one of the responsibilities you have when you hold your own funds is to protect them. Encrypting your wallet protects them from being spent without your permission, but you also should protect your funds from being lost just like you would with cash or any valuable item.
Your real wallet is not the program itself, but a file called wallet.dat which has a copy of your private key. Think of your private key as a magic key that lets you spend or save your money and proves you own it.
Since BitSeeds or Bitcoin are not physical money like cash, you have a big advantage with them in that you can make as many copies of your private key (wallet file) as you want, just as you can with any other file such as a Word document, or a photo, etc. So if you lose one copy, no worries, you just get one of your spares.
Just try doing that with cash!
This video shows you how to make a spare copy of your wallet.dat file. I cannot stress enough how important it is to back up all your important files, and you should consider your wallet file one of the most important files you own.
Fore more information on backing up, I’ll refer you to this older lesson on how to back up your Windows or Mac computer.