If you want to make sure that your Bitcoins don't get lost, you need to create a full backup of your wallet with your Bitcoin private keys. In addition, you'll need to create a hard copy of them somewhere that you are sure not to lose. But, the most important thing is to avoid your private keys getting into the wrong hands in the first place.

That's why you should keep your private keys safe from thieves, hackers, and/or accidental loss. These kinds of mishaps are one of the biggest threats to newbies and less experienced Bitcoin users. Don't ever take security lightly.